Methods and systems for fuel production

ABSTRACT

The present disclosure provides systems and methods for producing carbon products via electrochemical reduction from fluid streams containing a carbon-containing material, such as, for example, carbon dioxide. Electrochemical reduction systems and methods of the present disclosure may comprise micro- or nanostructured membranes for separation and catalytic processes. The electrochemical reduction systems and methods may utilize renewable energy sources to generate a carbon product comprising one or more carbon atoms (C1+ product), such as, for example, fuel. This may be performed at substantially low (or nearly zero) net or negative carbon emissions.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.17/338,947, filed Jun. 4, 2021, which is a continuation of InternationalApplication No. PCT/US2019/066787, filed Dec. 17, 2019, which is acontinuation-in-part of U.S. patent application Ser. No. 16/503,165,filed Jul. 3, 2019, now granted as U.S. Pat. No. 10,590,548, whichclaims priority from U.S. Provisional Patent Application No. 62/781,149,filed Dec. 18, 2018, each of which is incorporated herein by referencein its entirety for all purposes.

BACKGROUND

There is an increasing level of carbon-containing compounds, such ascarbon monoxide (CO) and carbon dioxide (CO₂), in the atmosphere. Suchincrease in level of carbon-containing compounds may be adverselyimpacting the global temperature, leading to global warming.

SUMMARY

Recognized herein is an increased need for efficient methods ofproducing fuels and other chemical commodities from non-petroleumsources. Such processes may utilize carbon monoxide (CO) and/or carbondioxide (CO₂) as a carbon-source for the production of organic moleculesto minimize the carbon footprint of the production and consumption ofthe produced fuels and chemicals. The production of durable chemicalproducts (e.g., polymers) may even create net carbon sinks for productsproduced using atmospheric carbon monoxide and/or carbon dioxide.

In an aspect, provided is a system for generating a carbon productcomprising one or more carbon atoms (C1+ product), comprising a firstcompartment, a second compartment, and a separation unit separating thefirst compartment and the second compartment, wherein the separationunit comprises (i) an anode, (ii) a cathode, and (iii) a membranecomprising a plurality of pores, wherein the plurality of pores areconfigured to bring the first compartment in fluid communication withthe second compartment, wherein the cathode and the anode are configuredto reduce the carbon-containing material to the C1+ product in the firstcompartment while a voltage is applied between the cathode and theanode, and wherein the plurality of pores are configured to direct theC1+ product from the first compartment to the second compartment.

In some embodiments, the system further comprises a gas contactor influid communication with the first compartment, wherein the gascontactor is configured to bring the carbon-containing material incontact with water to yield a solution comprising the carbon-containingmaterial. In some embodiments, the membrane comprises one or morematerials selected from the group consisting of carbon nanotubes, carbonnanospheres, carbon nano-onions, graphene, and porous pyrolyzed carbon.

In some embodiments, the cathode further comprises a catalyst. In someembodiments, the catalyst comprises a metal nanoparticle. In someembodiments, the metal nanoparticle comprise a metal selected from thegroup consisting of copper, nickel, platinum, iridium, ruthenium,palladium, tin, silver, and gold. In some embodiments, the catalyst isN-doped.

In some embodiments, the system further comprises a voltage sourceconfigured to supply the voltage. In some embodiments, the voltagesource comprises a renewable power source. In some embodiments, thevoltage source comprises one or more members selected from the groupconsisting of a photovoltaic power source, a wind power source, ageothermal power source, a hydroelectric power source, a tidal powersource, and nuclear power.

In some embodiments, the system further comprises an ion exchangemembrane between the cathode and the anode.

In some embodiments, the system is configured to have a single passselectivity for the C1+ product of at least about 70%.

In some embodiments, a pore of the plurality of pores has a pore size ofless than or equal to about 5 micrometers. In some embodiments, the poresize is less than or equal to about 500 nanometers. In some embodiments,the pore size is less than or equal to about 100 nanometers. In someembodiments, the pore size is less than or equal to about 50 nanometers.In some embodiments, the pore size is less than or equal to about 10nanometers. In some embodiments, the pore size is less than or equal toabout 5 nanometers.

In some embodiments, the C1+ product comprises one or more membersselected from the group consisting of methanol, ethanol, propanol, andbutanol.

In some embodiments, the first compartment comprises the cathode and thesecond compartment comprises the anode. In some embodiments, the firstcompartment comprises the cathode and the membrane. In some embodiments,the separation unit further comprises an extractor. In some embodiments,the extractor comprises the second compartment and the membrane.

In another aspect, a method is provided for using a carbon-containingmaterial to generate a carbon product comprising one or more carbonatoms (C1+ product), comprising providing an electrochemical a firstcompartment; a second compartment; and a separation unit separating thefirst compartment and the second compartment, wherein the separationunit comprises (i) an anode, (ii) a cathode, and (iii) a membranecomprising a plurality of pores, wherein the plurality of pores areconfigured to bring the first compartment in fluid communication withthe second compartment, directing an electrolyte solution comprising thecarbon-containing material into the first compartment, to bring theelectrolyte solution into contact with the cathode, wherein the anodeand the cathode are in electrical communication with one another throughthe electrolyte solution, and wherein a voltage is applied between thecathode and the anode, reducing the carbon-containing material in theelectrolyte solution while the voltage is applied between the cathodeand the anode, to generate the C1+ product, which C1+ product isdirected through the plurality of pores to the second compartment, andrecovering the C1+ product from the second compartment of theelectrochemical system.

In some embodiments, the cathode further comprises a catalyst. In someembodiments, the catalyst is used to reduce the carbon-containingmaterial in the electrolyte.

In some embodiments, the carbon-containing material comprises carbonmonoxide (CO) and/or carbon dioxide (CO₂).

In some embodiments, the electrolyte solution comprises an aqueousspecies resulting from an interaction of the carbon-containing materialwith water. In some embodiments, the aqueous species comprises one ormore members selected from the group consisting of bicarbonate ions,carbonate ions, and formate ions.

In some embodiments, the method further comprises, prior to the secondstep, introducing the carbon-containing material to water using a gascontactor. In some embodiments, the membrane comprises one or morematerials selected from the group consisting of carbon nanotubes, carbonnanospheres, carbon nano-onions, graphene, and porous pyrolyzed carbon.

In some embodiments, the membrane further comprises a catalyst. In someembodiments, the catalyst comprises metal nanoparticles. In someembodiments, the metal nanoparticles comprise a metal selected from thegroup consisting of copper, nickel, platinum, iridium, ruthenium,palladium, tin, silver, and gold. In some embodiments, the catalyst(s)is N-doped.

In some embodiments, the voltage is applied by a source that comprises arenewable power source. In some embodiments, the renewable power sourcecomprises one or members selected from the group consisting ofphotovoltaic power, wind power, geothermal power, hydroelectric power,tidal power, and nuclear power.

In some embodiments, the method further comprises introducing thecarbon-containing material to the electrochemical system by usinghydroxides generated electrochemically.

In some embodiments, the cathode operates at a temperature from about10° Celsius (C) to 40° C.

In some embodiments, the C1+ product is recovered from theelectrochemical reduction system in absence of a distillation unit.

In some embodiments, the electrochemical system further comprises an ionexchange membrane.

In some embodiments, the C1+ product is recovered from theelectrochemical reduction system at a single pass selectivity of atleast about 70%.

In some embodiments, the cathode comprises pores with pore sizes of nomore than about 5 micrometers.

In some embodiments, the C1+ product comprises one or more membersselected from the group consisting of methanol, ethanol, propanol, andbutanol.

In some embodiments, the pores have average cross-sectional dimensionsof no more than about 5 micrometers. In some embodiments, the averagecross-sectional dimensions are no more than about 500 nanometers. Insome embodiments, the average cross-sectional dimensions no more thanabout 100 nanometers. In some embodiments, the average cross-sectionaldimensions are no more than about 50 nanometers. In some embodiments,the average cross-sectional dimensions are no more than about 10nanometers. In some embodiments, the average cross-sectional dimensionsare no more than about 5 nanometers.

In another aspect, a method is provided for using a carbon-containingmaterial to generate a carbon product comprising one or more carbonatoms (C1+ product), comprising providing an electrochemical systemcomprising a first compartment, a second compartment, and a separationunit comprising (i) an anode, (ii) a cathode, and (iii) a micro- ornanostructured membrane comprising pores, wherein the cathode comprisesa catalyst(s), wherein the separation unit separates the firstcompartment and the second compartment, and wherein the firstcompartment is in fluid communication with the second compartmentthrough the pores, directing an electrolyte solution comprising thecarbon-containing material into the first compartment, to bring theelectrolyte solution in contact with the cathode, wherein the anode andthe cathode are in electrical communication with one another through theelectrolyte solution, and wherein a voltage is applied between thecathode and the anode, using the catalyst(s) to reduce thecarbon-containing material in the electrolyte solution while the voltageis applied between the cathode and the anode, to generate the C1+product, which C1+ product is directed through the pores to the secondcompartment, and recovering the C1+ product from the second compartmentof the electrochemical system.

In some embodiments, the carbon-containing material comprises carbonmonoxide (CO) and/or carbon dioxide (CO₂).

In some embodiments, the anode comprises a catalyst(s).

In some embodiments, the electrolyte solution comprises an aqueousspecies resulting from an interaction of the carbon-containing materialwith water. In some embodiments, the aqueous species comprises one ormore members selected from the group consisting of bicarbonate ions,carbonate ions, and formate ions.

In some embodiments, the method further comprises, prior to the secondstep, introducing the carbon-containing material to water using a gascontactor. In some embodiments, the gas contactor comprises a membrane.In some embodiments, the membrane comprises one or more nanomaterialsselected from the group consisting of carbon nanotubes, carbonnanospheres, carbon nano-onions, graphene, and porous pyrolyzed carbon.

In some embodiments, the micro- or nanostructured membrane comprises oneor more materials selected from the group consisting of carbonnanotubes, carbon nanospheres, carbon nano-onions, graphene, and porouspyrolyzed carbon.

In some embodiments, the micro- or nanostructured membrane furthercomprises a catalyst. In some embodiments, the catalyst comprises metalnanoparticles. In some embodiments, the metal nanoparticles comprise ametal selected from the group consisting of copper, nickel, platinum,iridium, ruthenium, palladium, tin, silver, and gold. In someembodiments, the catalyst(s) is N-doped.

In some embodiments, the voltage is applied by a source that comprises arenewable power source. In some embodiments, the renewable power sourcecomprises one or members selected from the group consisting ofphotovoltaic power, wind power, geothermal power, hydroelectric power,tidal power, and nuclear power.

In some embodiments, the method further comprises introducing thecarbon-containing material to the electrochemical system by usinghydroxides generated electrochemically.

In some embodiments, the cathode operates at a temperature from about10° Celsius (C) to 40° C.

In some embodiments, the C1+ product is recovered from theelectrochemical reduction system in absence of a distillation unit.

In some embodiments, the electrochemical system further comprises an ionexchange membrane configured to minimize a distance between the cathodeand the anode.

In some embodiments, the C1+ product is recovered from theelectrochemical reduction system at a single pass selectivity of atleast about 70%.

In some embodiments, the cathode comprises pores with pore sizes of nomore than about 5 microns.

In some embodiments, the C1+ product comprises one or more membersselected from the group consisting of methanol, ethanol, propanol, andbutanol.

In some embodiments, the pores have average cross-sectional dimensionsof no more than about 5 micrometers. In some embodiments, the averagecross-sectional dimensions are no more than about 500 nanometers. Insome embodiments, the pores have average cross-sectional dimensions ofno more than about 100 nanometers. In some embodiments, the pores haveaverage cross-sectional dimensions of no more than about 50 nanometers.In some embodiments, the pores have average cross-sectional dimensionsof no more than about 10 nanometers. In some embodiments, the pores haveaverage cross-sectional dimensions of no more than about 5 nanometers.

Another aspect of the present disclosure provides a non-transitorycomputer readable medium comprising machine executable code that, uponexecution by one or more computer processors, implements any of themethods above or elsewhere herein.

Another aspect of the present disclosure provides a system comprisingone or more computer processors and computer memory coupled thereto. Thecomputer memory comprises machine executable code that, upon executionby the one or more computer processors, implements any of the methodsabove or elsewhere herein.

Additional aspects and advantages of the present disclosure will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein only illustrative embodiments of thepresent disclosure are shown and described. As will be realized, thepresent disclosure is capable of other and different embodiments, andits several details are capable of modifications in various obviousrespects, all without departing from the disclosure. Accordingly, thedrawings and description are to be regarded as illustrative in nature,and not as restrictive.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings (also “figure” and “FIG.” herein), of which:

FIG. 1A depicts a cross-sectional and face-oriented schematic view of amicro- or nanostructured membrane material comprising nanotubes. Arrowsdepict pore space that may permit the selective passage of particularchemical species.

FIG. 1B depicts a cross-sectional and face-oriented schematic view of amicro- or nanostructured membrane material comprising nano-onions.Arrows depict pore space that may permit the selective passage ofparticular chemical species.

FIG. 1C depicts a cross-sectional and face-oriented schematic view of amicro- or nanostructured membrane material comprising a pyrolyzed porousmaterial. Arrows depict pore space that may permit the selective passageof particular chemical species.

FIG. 1D depicts a cross-sectional and face-oriented schematic view of amicro- or nanostructured membrane material comprising a graphene-likematerial. Arrows depict pore space that may permit the selective passageof particular chemical species.

FIG. 2 depicts an illustration of a carbon nanotube embedded in amembrane material.

FIG. 3A depicts a micro- or nanostructured membrane configured in acylindrical fashion (such as a hollow fiber).

FIG. 3B shows a detailed illustration of a small region of the membranesurface that comprises carbon nanotubes.

FIG. 4 illustrates a representative graphene-like material of thepresent invention.

FIG. 5 shows an illustration of a catalyst nanoparticle associated witha carbon nanotube as provided in the present disclosure.

FIG. 6 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 7 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 8 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 9 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 10 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 11 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 12 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 13 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 14 depicts a schematic of another embodiment of an electrochemicalreduction system for the conversion of CO or CO₂ to hydrocarbons.

FIG. 15 illustrates a schematic of a computer system as utilized for thepresent invention.

FIG. 16A depicts a schematic of a separation unit comprising a firstcompartment with a cathode and a second compartment with an anode.

FIG. 16B depicts a schematic of a separation unit comprising a firstcompartment containing a cathode.

FIG. 16C depicts a schematic view of a separation unit comprising anextractor unit comprising a membrane and a second compartment.

DETAILED DESCRIPTION

While various embodiments of the invention have been shown and describedherein, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. Numerous variations,changes, and substitutions may occur to those skilled in the art withoutdeparting from the invention. It should be understood that variousalternatives to the embodiments of the invention described herein may beemployed.

Whenever the term “at least,” “greater than,” or “greater than or equalto” precedes the first numerical value in a series of two or morenumerical values, the term “at least,” “greater than” or “greater thanor equal to” applies to each of the numerical values in that series ofnumerical values. For example, greater than or equal to 1, 2, or 3 isequivalent to greater than or equal to 1, greater than or equal to 2, orgreater than or equal to 3.

Whenever the term “no more than,” “less than,” or “less than or equalto” precedes the first numerical value in a series of two or morenumerical values, the term “no more than,” “less than,” or “less than orequal to” applies to each of the numerical values in that series ofnumerical values. For example, less than or equal to 3, 2, or 1 isequivalent to less than or equal to 3, less than or equal to 2, or lessthan or equal to 1.

The terms “C1+” and “C1+ compound,” as used herein, generally refer to acompound comprising one or more carbon atoms, e.g., one carbon atom(C1), two carbon atoms (C2), etc. C1+ compounds include, withoutlimitation, alkanes (e.g., methane, CH₄), alkenes (e.g., ethylene,C₂H₂), alkynes and aromatics containing two or more carbon atoms. Insome cases, C1′+ compounds include aldehydes, ketones, esters andcarboxylic acids. Examples of C1+ compounds include, without limitation,methane, ethane, ethylene, acetylene, propane, propene, butane,butylene, etc.

The term “unit,” as used herein, generally refers to a unit operation,which is a basic operation in a process. Unit operations may involve aphysical change or chemical transformation, such as, for example,separation, crystallization, evaporation, filtration, polymerization,isomerization, transformation, and other reactions. A given process mayrequire one or a plurality of unit operations to obtain the desiredproduct(s) from a starting material(s), or feedstock(s).

The term “carbon-containing material,” as used herein, generally refersto any material comprising at least one carbon atom. In some example, acarbon-containing material is carbon monoxide (CO), carbon dioxide(CO₂), or a mixture of CO and CO₂. The carbon-containing material may bea material derived from CO and/or CO₂, such as bicarbonate orbicarbonate ions.

Provided herein are systems and methods for producing various chemicalproducts, including hydrocarbon fuels, from a source comprising acarbon-containing material, such as carbon monoxide (CO) and/or carbondioxide (CO₂). The source may be a gas source or a liquid source. Insome instances, the gas source comprising CO or CO₂ may be air drawndirectly from the atmosphere. In other instances, the gas sourcecomprising CO or CO₂ may be an effluent gas such as flue gas from acombustion process. In the present invention, a gas stream comprising COor CO₂ may be drawn into an electrochemical reduction system thatconverts CO or CO₂ into hydrocarbons. The described systems may includeone or more additional chemical conversion processes that allow theconversion of the CO- or CO₂-derived hydrocarbons into other valuablechemical products.

Also provided herein are various configurations for an electrochemicalreduction system that converts CO or CO₂ into hydrocarbons. In someinstances, the electrochemical reduction system may operate at anambient temperature. The electrochemical reduction system may compriseone or more membranes that comprise a micro- or nanostructured materialsuch as carbon nanotubes (CNTs) or graphene.

Microstructured material may have dimensions on the order of 1micrometer to 1000 micrometers, or 1 micrometer to 100 micrometers, or 1micrometer to 10 micrometers. Nanostructured material may havedimensions on the order of 1 nanometer to 1000 nanometers, 1 nanometerto 100 nanometers, or 1 nanometer to 10 nanometers.

Microstructured material may have dimensions less than or equal to 1000micrometers, 100 micrometers, 10 micrometers, 1 micrometer, or less.Nanostructured material may have dimensions less than or equal to 1000nanometers, 100 nanometers, 10 nanometers, 1 nanometers, or less.

In some instances, the micro- or nanostructured membranes may be capableof selectively separating CO or CO₂ from a mixed gas stream. In otherinstances, the micro- or nanostructured membranes may be capable ofselectively separating certain hydrocarbons from a liquid or gaseousmedium. Also provided herein are micro- or nanostructured membranes thatcomprise catalysts for the conversion of CO or CO₂ into hydrocarbons. Insome instances, the micro- or nanostructured membrane may be configuredto comprise an anode or cathode in an electrochemical reduction system.

Provided herein are various products that may be produced by the systemsand methods described herein. The electrochemical reduction systems mayproduce alkanes, alkenes, alcohols, or other organic molecules ofvarying chain lengths. The products of the described electrochemicalreduction systems may be further processed into other fuel and chemicalproducts, such as polymers. The selectivity of the micro- ornanostructured membranes utilized in the electrochemical reductionsystems may allow chemical products to be produced with tailoredmolecular weight ranges and increased purity from processing byproducts(e.g. metals, salts and other undesired inputs or products).

Also provided herein are systems of varying scale for producingchemicals from a gas stream comprising CO or CO₂. In some instances,chemicals may be produced from a chemical plant that comprises one ormore CO or CO₂ electrochemical reduction systems. In other instances,chemicals may be produced from CO or CO₂ as a subsystem of a largerfacility, for example as a scrubber on a power-generation facility. Inother instances, chemicals may be produced using small-scale or evenmicro-scale devices. In some instances, an electrochemical reductionsystem utilizing a gas source comprising CO or CO₂ may be coupled with arenewable electrical generation sources (e.g. photovoltaics) to create afully sustainable method of chemical production. In some instances, thesystem and methods described herein may be net carbon negative (i.e.they sequester more carbon than they produce). In some instances, thesystems described herein may decrease the energy input of a chemicalproduction process by at least about 50%.

Chemical Products

Described herein are various chemical products and reaction mixturesgenerated via the electrochemical reduction of CO or CO₂ derived from agas source. Chemical products may include any process streams that isexported from a chemical processing system or any process stream thatundergoes no further reactive processes. A reaction mixture may includeany process mixture, reagent, or compound within the confines of achemical reactor, reactor system, or in a process stream betweenchemical reactors or reactor systems. The chemical products and reactionmixtures of the present invention may include organic molecules whereone or more of the constituent carbon atoms are derived from CO or CO₂.In some instances a chemical product or reaction mixture may containonly carbon atoms derived from CO or CO₂. In other instances, a chemicalproduct may contain carbon atoms derived from CO or CO₂ and carbon atomsderived from other sources (e.g. fossil fuels). In some instances,chemical products of the present invention may have a distinct carbonisotope signature that is consistent with the carbon isotope signatureof CO or CO₂ derived from the atmosphere. In some instances, chemicalproducts and reaction mixtures of the present invention may have adistinct carbon isotope signature that is consistent with the carbonisotope signature of CO or CO₂ derived from a non-atmospheric sourcesuch as the combustion of fossil fuels. The carbon isotope signature ofa chemical product or reaction mixture may be measured by an isotopicratio of ¹⁴C:¹²C or ¹³C:¹²C. In some instances the isotopic signature ofa chemical product or reaction mixture may be measured as a percentdifference between the natural isotopic ratio of carbon and the measuredisotopic ratio. A percent difference between the natural isotopic ratioof carbon and the measured isotopic ratio for ¹⁴C, Δ¹⁴C, may becalculated as:

${\Delta^{14}C} = {\left\lbrack {\frac{\left\lbrack \frac{\,^{14}C}{\,^{12}C} \right\rbrack_{measured}}{\left\lbrack \frac{\,^{14}C}{\,^{12}C} \right\rbrack_{standard}} - 1} \right\rbrack x1000\%}$

A percent difference between the natural isotopic ratio of carbon andthe measured isotopic ratio for ¹³C, Δ¹³C, may be calculated as:

${\Delta^{13}C} = {\left\lbrack {\frac{\left\lbrack \frac{\,^{13}C}{\,^{12}C} \right\rbrack_{measured}}{\left\lbrack \frac{\,^{13}C}{\,^{12}C} \right\rbrack_{standard}} - 1} \right\rbrack x1000\%}$

A chemical product or reaction mixture may have a Δ¹⁴C of about −100%,−10%, 0%, 5%, 10%, 20%, 30%, 40%, 45%, 50% or about 100%. A chemicalproduct or reaction mixture may have a Δ¹³C of about −40%, −35%, −30%,−28%, −26%, −24%, −22%, −20%, −15%, −10%, −8%, or about −5%.

A chemical product or reaction mixture of the present invention mayinclude gaseous, liquid, or solid substances. Chemical products andreaction mixtures of the current invention may include one or moreorganic compounds. Chemical products and reaction mixtures may bemiscible or immiscible in water. Chemical products and reaction mixturesmay be polar or nonpolar. Chemical products and reaction mixtures may beacidic, basic, or neutral. Organic compounds may include alkanes,alkenes, alkynes, cycloalkanes, cycloalkenes, cycloalkynes, substitutedalkanes, substituted alkenes, substituted alkynes, alcohols, esters,carboxylic acids, ethers, amines, amides, aromatics, heteroaromatics,sulfides, sulfones, sulfates, thiols, aldehydes, ketones, amides, andhalogenated compounds. Chemical products and reaction mixtures mayinclude branched or linear compounds. Chemical products and reactionmixtures may comprise oxygen, methane, ethane, ethylene, propane,butane, hexanes, octanes, decanes, carbon monoxide, methanol, ethanol,propanol, butanol, hexanol, octanol, and formate. Chemical products andreaction mixtures may include organometallic compounds. Chemicalproducts and reaction mixtures of the present disclosure may includecompounds intended for consumer use or industrial use, such as fuels,solvents, additives, polymers, food additives, food supplements,pharmaceuticals, fertilizers, agricultural chemicals, coatings,lubricants, and building materials. Chemical products and reactionmixtures of the present disclosure may comprise a precursor, component,substituent, or substrate for a product produced by further processing.

An organic compound of the present disclosure may comprise one or morecarbon atoms. In some instances, an organic compound may comprise about1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 60, 65, or about 70carbon atoms. In some instances, an organic compound may comprise atleast about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60,65, or about 70 or more carbon atoms. In some instances, an organiccompound may comprise no more than about 70, 65, 60, 55, 50, 45, 40, 30,29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12,11, 10, 9, 8, 7, 6, 4, 3, 2 or less carbon atoms. An organic compound ofthe present disclosure may comprise one or more carbon atoms derivedfrom CO or CO₂. In some instances, an organic compound may compriseabout 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65,or about 70 carbon atoms that are derived from CO or CO₂. In someinstances, an organic compound may comprise at least about 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, or about 70 ormore carbon atoms that are derived from CO or CO₂. In some instances, anorganic compound may comprise no more than about 65, 60, 55, 50, 45, 40,35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14,13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or less carbon atoms that arederived from CO or CO₂.

A chemical product or reaction mixture of the present disclosure maycomprise more than one chemical species. A chemical product or reactionmixture may be a mixture of about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or about 100detectable chemical compounds. A chemical product or reaction mixturemay be a mixture of at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or about 100 or moredetectable chemical compounds. A chemical product or reaction mixturemay be a mixture of no more than about 100, 95, 90, 85, 80, 75, 70, 65,60, 55, 50, 45, 40, 35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 19, 18,17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, or no more than about3 or less detectable chemical compounds.

A chemical product or reaction mixture of the present disclosure maycomprise a particular compound at a particular weight percentage ormolar percentage of the total chemical product or reaction mixture. Forexample, a particular chemical product may include at least about 50 wt% ethanol. In another example, a particular chemical product may includeno more than about 1 wt % water. In some instances, at least about 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 96%, 97%, 98%, 99% or more of a chemical product orreaction mixture may be a specific chemical compound on a weight ormolar basis. In some instances, no more than about 99%, 98%, 97%, 96%,95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%,25%, 20%, 15%, or no more than about 10% or less of a chemical productor reaction mixture be a specific chemical compound on a weight or molarbasis.

A chemical product or reaction mixture of the present disclosure mayinclude compounds within a particular range of molecular weights orcarbon numbers. In some instances, at least about 10%, 15%, 20%, 25%,30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%,96%, 97%, 98%, 99% or more of a chemical product or reaction mixture mayinclude compounds within a particular molecular weight range or carbonnumber range. In some instances, no more than about 99%, 98%, 97%, 96%,95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%,25%, 20%, 15%, or no more than about 10% or less of a chemical productor reaction mixture may include compounds within a particular molecularweight range or carbon number range. A chemical product or reactionmixture may include compounds within a molecular weight range from about15 g/mol to about 30 g/mol, about 15 g/mol to about 60 g/mol, about 15g/mol to about 100 g/mol, about 15 g/mol to about 200 g/mol, about 15g/mol to about 400 g/mol, about 15 g/mol to about 600 g/mol, about 15g/mol to about 1000 g/mol, about 30 g/mol to about 60 g/mol, about 30g/mol to about 100 g/mol, about 30 g/mol to about 200 g/mol, about 30g/mol to about 400 g/mol, about 30 g/mol to about 600 g/mol, about 30g/mol to about 1000 g/mol, about 60 g/mol to about 100 g/mol, about 60g/mol to about 200 g/mol, about 60 g/mol to about 400 g/mol, about 60g/mol to about 600 g/mol, about 60 g/mol to about 1000 g/mol, about 100g/mol to about 200 g/mol, about 100 g/mol to about 400 g/mol, about 100g/mol to about 600 g/mol, about 100 g/mol to about 1000 g/mol, about 200g/mol to about 400 g/mol, about 200 g/mol to about 600 g/mol, about 200g/mol to about 1000 g/mol, about 400 g/mol to about 600 g/mol, about 30g/mol to about 1000 g/mol, about 30 g/mol to about 100 g/mol, about 30g/mol to about 200 g/mol, about 30 g/mol to about 400 g/mol, about 30g/mol to about 600 g/mol, about 400 g/mol to about 1000 g/mol, or about600 g/mol to about 1000 g/mol. A chemical product or reaction mixturemay include compounds within a carbon number range from about C1 toabout C2, about C1 to about C3, about C1 to about C4, about C1 to aboutC5, about C1 to about C6, about C1 to about C8, about C1 to about C10,about C1 to about C20, about C1 to about C30, about C1 to about C40,about C2 to about C3, about C2 to about C4, about C2 to about C5, aboutC2 to about C6, about C2 to about C8, about C2 to about C10, about C2 toabout C20, about C2 to about C30, about C2 to about C40, about C3 toabout C4, about C3 to about C5, about C3 to about C6, about C3 to aboutC8, about C3 to about C10, about C3 to about C20, about C3 to about C30,about C3 to about C40, about C4 to about C5, about C4 to about C6, aboutC4 to about C8, about C4 to about C10, about C4 to about C20, about C4to about C30, about C4 to about C40, about C5 to about C6, about C5 toabout C8, about C5 to about C10, about C5 to about C20, about C5 toabout C30, about C5 to about C40, about C6 to about C8, about C6 toabout C10, about C6 to about C20, about C6 to about C30, about C6 toabout C40, about C8 to about C10, about C8 to about C20, about C8 toabout C30, about C8 to about C40, about C10 to about C20, about C10 toabout C30, about C10 to about C40, about C20 to about C30, about C20 toabout C40, or about C30 to about C40.

A chemical product or reaction mixture of the present disclosure maycomprise one or more impurities. Impurities may derive from reactantstreams, reactor contaminants, breakdown or decomposition products ofproduced organic compounds, catalyst compounds, or side reactions in theelectrochemical reduction system or other chemical conversion systemsdescribed herein. A chemical product or reaction mixture may compriseone or more organic impurities such as formate or higher molecularweight alcohols. A chemical product or reaction mixture may includecarbon or non-carbon nanomaterial impurities. A chemical product orreaction mixture may comprise one or more inorganic impurities derivedfrom sources such as catalyst degradation or leaching and corrosion ofprocessing equipment. An inorganic impurity may comprise sodium,magnesium, potassium, calcium, titanium, vanadium, chromium, manganese,iron, cobalt, nickel, copper, zinc, aluminum, silicon, yttrium,zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver,cadmium, indium, tin, antimony, tantalum, tungsten, osmium, platinum,gold, mercury, and lead. Inorganic impurities may be present in oxidizedor reduced oxidation states. Inorganic impurities may be present in theform of organometallic complexes. An impurity in a chemical product orreaction mixture may be detectable by any common analysis technique suchas gas or liquid chromatography, mass spectrometry, IR or UV-Visspectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy,X-ray diffraction, or other methods. One or more impurities may bedetectable at an amount of at least about 1 part per billion (ppb), 5ppb, 10 ppb, 50 ppb, 100 ppb, 250 ppb, 500 ppb, 750 ppb, 1 part permillion (ppm), 5 ppm, 10 ppm, 50 ppm, 100 ppm or more. One or moreimpurities may be detectable at an amount of no more than about 100 ppm,50 ppm, 10 ppm, 5 ppm, 1 ppm, 750 ppb, 500 ppb, 250 ppb, 100 ppb, 50ppb, 10 ppb, 5 ppb, or no more than about 1 ppb or less.

A chemical product may have a particular level of purity. In someinstances, a chemical product may have sufficient purity to achieve aparticular grade or standard. A chemical product may be ACS grade,reagent grade, USP grade, NF grade, laboratory grade, purified grade ortechnical grade. A chemical product may have a purity that exceeds anazeotropic composition, e.g. >95% ethanol. A gaseous chemical product ofthe current invention may have a purity rating of about N1.0, N2.0,N3.0, N4.0, N5.0, N6.0 or greater. A chemical product may achieve apurity level according to a defined international standard. E.g. theASTM D-1152/97 standard for methanol purity.

In some instances a chemical product or reaction mixture from anelectrochemical reduction system may have no detectable amount ofcertain impurities. In some instances, a chemical product or reactionmixture may have no detectable amount of biological molecules orderivatives thereof. A chemical product or reaction mixture may containno detectable amount of lipids, saccharides, proteins, nucleic acids,amino acids, spores, bacteria, viruses, protozoa, fungi, animal or plantcells, or any component thereof.

Chemical Feeds

The electrochemical conversion systems and related systems may requireone or more feed streams. Feed streams may comprise solids, liquids orgases. Feed streams may comprise slurries, pastes, powders, particles,or bed materials. In some instances, a feed stream may comprise one ormore chemical reactants. In other instances, a feed stream may comprisea catalyst, a co-catalyst, an activator, an inhibitor, a buffer, or areactive scavenger. In some instances, a feed stream may comprise aninert species.

A feed stream may comprise a gas or a mixture of gases. In someinstances, a gas stream may comprise CO, CO₂, nitrogen, a nitrogenoxide, oxygen, ozone, argon, hydrogen, helium, methane, ethane,ethylene, propane, propylene, hydrogen sulfide, a sulfur oxide, silanes,aromatics, chlorine, hydrochloric acid, sulfuric acid, nitric acid,water vapor, and other gases. In some instances, a gas stream maycomprise air drawn directly from the atmosphere. In other instances, agas stream may comprise effluent gases from an industrial or othersource. In some instances, a gas stream may comprise suspendedparticulates such as soot, pollen, spores, dust, and mineral matter orash. A gas stream may comprise an aerosol. A gas stream may be filteredor scrubbed to remove particulates or unwanted chemical species. A gasstream may be subjected to one or more operations before entering achemical conversion process or other process to alter its composition orotherwise prepare the gas stream for utilization. A gas stream may beseparated or purified to enrich for a particular component (e.g. CO₂) orremove an unwanted component (e.g. hydrogen sulfide).

A feed stream may comprise a liquid or a mixture of liquids. In someinstances, a liquid stream may comprise a chemical reactant. In otherinstances, a liquid stream may comprise a solvent carrying a chemicalreactant. A liquid stream may comprise a buffered solution, e.g.bicarbonate solution. A liquid stream may comprise one or more ofalkanes, alkenes, alkynes, cycloalkanes, cycloalkenes, cycloalkynes,substituted alkanes, substituted alkenes, substituted alkynes, alcohols,esters, carboxylic acids, ethers, amines, amides, aromatics,heteroaromatics, sulfides, sulfones, sulfates, thiols, aldehydes,ketones, amides, and halogenated compounds.

A liquid feed stream may comprise an aqueous solution. An aqueoussolution may be buffered to maintain a particular pH. A feed stream mayhave a pH of about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, orabout 14. A feed stream may have a pH of at least about 0, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or more. A feed stream may have a pHof no more than about 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0or less.

A feed stream may be a multi-phase stream. A feed stream may comprisegas entrained in a liquid or a solid entrained in a liquid, such as aslurry. A feed stream may exist in a phase equilibrium between solid andliquid, liquid and gas, or solid and gas.

A feed stream may comprise one or more impurities or tracer compounds.Impurities in a feed stream may arise from the processes that producedthem or transportation methods used to convey the feed stream matterfrom production to the systems of the present disclosure. Impurities mayinclude organic or inorganic chemical species, particulates (e.g. dirt,dust, rust, or ash), and biological materials. An impurity may bedetrimental to the performance of an electrochemical reduction system orrelated system. An inorganic impurity may comprise sodium, magnesium,potassium, calcium, titanium, vanadium, chromium, manganese, iron,cobalt, nickel, copper, zinc, aluminum, silicon, yttrium, zirconium,niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium,indium, tin, antimony, tantalum, tungsten, osmium, platinum, gold,mercury, and lead. Inorganic impurities may be present in oxidized orreduced oxidation states. Inorganic impurities may be present in theform of organometallic complexes. A feed stream may be purified beforeuse to remove one or more impurities before utilization in anelectrochemical reduction system or a related system. A tracer compoundmay comprise a chemical species that exists at a low but detectablelevel within a feed stream. A tracer compound may be come in aparticular feed stream reagent or may be added to a feed stream prior tothe feed stream entering a conversion or other process. A tracercompound may be an inert species. A tracer compound may be a compoundthat is selectively converted, separated, or otherwise altered incertain processes and is unaffected by other processes. An impurity or atracer compound may have a measured concentration in a feed stream. Animpurity or a tracer compound in a chemical product may be detectable byany common analysis technique such as gas or liquid chromatography, massspectrometry, IR or UV-Vis spectroscopy, Raman spectroscopy, X-rayphotoelectron spectroscopy, X-ray diffraction, or other methods. One ormore impurities or tracer compounds may be detectable at an amount of atleast about 1 ppb, 5 ppb, 10 ppb, 50 ppb, 100 ppb, 250 ppb, 500 ppb, 750ppb, 1 ppm, 5 ppm, 10 ppm, 50 ppm, 100 ppm or more. One or moreimpurities or tracer compounds may be detectable at an amount of no morethan about 100 ppm, 50 ppm, 10 ppm, 5 ppm, 1 ppm, 750 ppb, 500 ppb, 250ppb, 100 ppb, 50 ppb, 10 ppb, 5 ppb, or no more than about 1 ppb orless.

Structured Membranes

The present disclosure may provide reactor and separation systems thatcomprise micro- or nanostructured membranes. A micro- or nanostructuredmembrane may be utilized to perform a selective separation of one ormore chemical species from a mixture comprising more than one chemicalspecies. A micro- or nanostructured membrane may also provide additionalutility in a chemical processing system including physically separatingproduct streams and comprising a component of an electrical cathode oranode in an electrochemical system.

A micro- or nanostructured membrane may comprise one or more microscaleor nanoscale materials features (e.g., including positive features, suchas microscale or nanoscale structures, and/or negative features, such asmicroscale and nanoscale pores or microscale and nanoscale depressions).In some instances, a membrane may comprise carbon nanotubes, carbonnanospheres, carbon nano-onions, graphene-like materials, or pyrolyzedporous carbon materials (see FIGS. 2 and 4 ). A membrane may comprisemicro- or nanostructured material synthesized from non-carbon materials.A membrane may comprise carbon nanomaterials doped with other elementssuch as nitrogen, sulfur, and boron. A micro- or nanostructured materialmay be embedded, fixed, or otherwise bound to one or more othersubstrates or materials to construct a membrane. A micro- ornanostructured material embedded in a substrate or material may createpores within the structured membrane. The pores may permit the selectivepassage of certain chemical species. Other substrates or materials inthe membrane may be selected for material properties including rigidity,strength, and electrical conductivity. Other substrates or materials ina micro- or nanostructured membrane may include polymers, e.g.polysulfones, metals, and ceramics. The microscale or nanoscale featuresmay have a maximum dimension of at least about 0.4 nanometers (nm), 0.6nm, 0.8 nm, 1 nm, 1.2 nm, 1.4 nm, 1.6 nm, 1.8 nm, 2.0 nm, 2.5 nm, 3.0nm, 3.5 nm, 4.0 nm, 4.5 nm, 5.0 nm, 5.5 nm, 6.0 nm, 6.5 nm, 7.0 nm, 7.5nm, 8.0 nm, 8.5 nm, 9.0 nm. 9.5 nm. 10 nm, 20 nm, 30 nm, 40 nm, 50 nm,60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600nm, 700 nm, 800 nm, 900 nm, 1 micrometer, 10 micrometers, 100micrometers or larger. In some instances, the maximum dimension may beat most about 100 micrometers, 10 micrometers, 1 micrometer, 900 nm, 800nm, 700 nm. 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 90 nm, 80nm, 70 nm, 60 nm, 50 nm, 40 nm, nm, 20 nm, 10 nm, 9.5 nm, 9.0 nm, 8.5nm, 8 nm, 7.5 nm, 7.0 nm, 6.5 nm, 6.0 nm, 5.5 nm, nm, 4.5 nm, 4.0 nm,3.5 nm, 3.0 nm, 2.5 nm, 2.0 nm, 1.8 nm, 1.6 nm, 1.4 nm, 1.2 nm, 1.0 nm,0.8 nm, 0.6 nm, or 0.4 nm or less.

A micro- or nanostructured membrane may comprise a particular shape,structure depending upon its application. In some instances, a membranemay have a cylindrical structure (see FIGS. 3A and 3B) such as with ahollow fiber membrane format, or have a substantially flat sheetstructure. A membrane may partially or fully enclose a volume or voidspace. The surface area of a membrane disposed toward an enclosed orvoid space may be defined as a lumen side of the membrane. In someinstances, mass transfer across a membrane may be driven by chemicalpotential, pressure difference, or temperature difference between alumen side and a non-lumen side of a membrane. A membrane may furthercomprise additional structures such as frames or fittings that securethe membrane to other portions of the described systems.

A micro- or nanostructured membrane may be composed with micro- ornanomaterials embedded so as to create pores within the membrane. Themicro- or nanomaterial may be chosen based upon a characteristic poresize that it may create. Without wanting to be bound by theory, a poremay be defined as a void space or volume within a solid material throughwhich a liquid or gas molecule may flow or diffuse. A chemical speciesmay pass through a pore created by the internal diameter space in acarbon nanotube (see FIG. 1A), through spaces between nanoparticles e.g.clustered nanotubes or nano-onions (see FIG. 1B), through the pores of aporous carbon (see FIG. 1C), or through the space between layers ofgraphene-like material (see FIG. 1D). A micro- or nanomaterial may havea characteristic length scale such as a diameter, pore size, or layerspacing that is sufficient to permit the passage of chemical speciesthrough a void space in the material. In some instances, acharacteristic length may be at least about 0.4 nanometers (nm), 0.6 nm,0.8 nm, 1 nm, 1.2 nm, 1.4 nm, 1.6 nm, 1.8 nm, 2.0 nm, 2.5 nm, 3.0 nm,4.0 nm, 5.0 nm or larger. In some instances, a characteristic length maybe no more than about 5.0 nm, 4.0 nm, 3.0 nm, 2.5 nm, 2.0 nm, 1.8 nm,1.6 nm, 1.4 nm, 1.2 nm, 1.0 nm, 0.8 nm, 0.6 nm, or about 0.4 nm or less.A pore may have a larger diameter than length. A pore may have a largerlength than diameter. A pore may have a length to width ratio of about1:10, 1:5, 1:2, 1:1, 2:1, 5:1, 10:1, 100:1, or about 1000:1. A pore mayhave a length to width ratio of at least about 1:10, 1:5, 1:2, 1:1, 2:1,5:1, 10:1, 100:1, or about 1000:1. A pore may have a length to widthratio of no more than about 1000:1, 100:1, 10:1, 5:1, 2:1, 1:1, 1:2,1:5, or about 1:10 or less. A pore may comprise a substantially straightpath such as a carbon nanotube or the space between layers of horizontalgraphene-like materials. A pore may have a diagonal, skewed, or tortuouspath in some materials, such as meso- or nanoporous carbons.

A membrane may comprise a material with a characterized porousstructure. Materials may include nanopores, mesopores, and micropores.In some instances, nanopores may be characterized as having an averagepore size of about 2 nm or less. In some instances, mesopores may becharacterized as having an average pore size of between about 2 nm andabout 20 nm. In some instances, micropores may be characterized ashaving an average pore size of about 20 nm or more. A membrane maycomprise structures with pore sizes across a range of pores sizes (e.g.,nanopores and mesopores). A membrane may comprise structures with poressizes from within a particular classification of pores sizes (e.g., onlymesopores). Pores may have circular, oval, non-circular or irregularpore shapes or pore cross-section profiles. A pore size may becharacterized as an average characteristic cross-sectional dimension(e.g., pore diameter or cross-sectional area). A membrane may comprisepores (e.g., micropores or nanopores) with an average cross-sectionaldimension of at least about nm, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 30 nm,40 nm, 50 nm, 100 nm, 250 nm, 500 nm, 1 micron (μm), or at least about 5μm or more. A membrane may comprise pores with an averagecross-sectional dimension of no more than about 5 μm, 1 μm, 500 nm, 250nm, 100 nm, 50 nm, 40 nm, 30 nm, 20 nm, 15 nm, 10 nm, 5 nm, 1 nm, 0.5 nmor less.

A membrane comprising a micro- or nanostructured material may permitmass transport of one or more chemical species across the membrane. Amembrane comprising a micro- or nanostructured material may be selectivefor particular species. In some instances, a membrane comprising micro-or nanostructured materials may selectively transfer CO or CO₂ from agas stream. In some instances, a membrane comprising micro- ornanostructured materials may selectively transfer gaseous ethylene orethanol from a gas mixture. In some instances, a membrane comprisingmicro- or nanostructured materials may selectively transfer hydrocarbonsfrom an aqueous liquid mixture. A membrane comprising a micro- ornanostructured material may transfer particular chemical species bydiffusive or convective mass transport. In some instances, mass transfermay be enhanced by the application of an external force or field. Inparticular instances, mass transfer may be driven or enhanced by theapplication of a magnetic or electrical field. In other instances, masstransfer may be driven by a pressure gradient (e.g. pulling a vacuum onone side of the membrane). In some instances, the selectivity of amembrane can be reversed by reversing an applied field or force. Inother instances, a membrane may have a unidirectional or invariant masstransfer selectivity.

A micro- or nanostructured membrane may have an optimal or preferredoperation temperature and operation pressure. In some instances, asystem comprising a micro- or nanostructured membrane may be operated atan ambient pressure or temperature. In some instances, a systemcomprising a micro- or nanostructured membrane may be operated at anelevated pressure or under a vacuum or reduced pressure. A pressuregradient may be utilized to drive mass transfer across a membranesystem. A micro- or nanostructured membrane may be utilized in a systemwith an operating temperature of about −30° C., −20° C., −10° C., 0° C.,5° C., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 50° C., 60° C.,70° C., or about 80° C. A micro- or nanostructured membrane may beutilized in a system with an operating temperature of at least about−30° C., −20° C., −10° C., 0° C., 5° C., 10° C., 15° C., 20° C., 25° C.,30° C., 35° C., 40° C., 50° C., 70° C., or about 80° C. or more. Amicro- or nanostructured membrane may be utilized in a system with anoperating temperature of no more than about 80° C., 75° C., 70° C., 65°C., 60° C., 50° C., 45° C., 40° C., 35° C., 30° C., 25° C., 20° C., 15°C., 10° C., 5° C., 0° C., −5° C., −10° C., −20° C., or about −30° C. orless.

A micro- or nanostructured membrane may be utilized in a system with anoperating pressure of about 0 bar, 1 bar, 2 bar, 3 bar, 4, bar, 5 bar, 6bar, 7 bar, 8 bar, 9 bar, bar, 15 bar, 20 bar, 30 bar, 40 bar, 50 bar ormore. A micro- or nanostructured membrane may be utilized in a systemwith an operating pressure of at least about 1 bar, 2 bar, 3 bar, 4,bar, 5 bar, 6 bar, 7 bar, 8 bar, 9 bar, 10 bar, 15 bar, 20 bar, 30 bar,40 bar, 50 bar or more. A micro- or nanostructured membrane may beutilized in a system with an operating pressure of no more than about 50bar, 40 bar, 30 bar, 20 bar, 15 bar, 10 bar, 9 bar, 8 bar, 7 bar, 6 bar,5 bar, 4 bar, 3 bar, 2 bar, 1 bar or less.

A micro- or nanostructured membrane may be capable of permitting aparticular flux of CO or CO₂ across the membrane. A flux of CO or CO₂may be driven by a pressure gradient across the membrane. In someinstances, a pressure gradient may be driven by a gas stream comprisingCO or CO₂ at a pressure elevated above ambient pressure. In otherinstances, a pressure gradient may exist by pulling a vacuum on one sideof the membrane, e.g. the lumen side. A micro- or nanostructuredmembrane may permit a CO or CO₂ flux of about 0.1 kilogram gas/m² ofmembrane/hr (kg/m²/hr), 0.5 kg/m²/hr, 1 kg/m²/hr, 2 kg/m²/hr, 3kg/m²/hr, 4 kg/m²/hr, 5 kg/m²/hr, 6 kg/m²/hr, 7 kg/m²/hr, 8 kg/m²/hr, 9kg/m²/hr, or about 10 kg/m²/hr. A micro- or nanostructured membrane maypermit a CO or CO₂ flux of at least about 0.1 kg/m²/hr, 0.5 kg/m²/hr, 1kg/m²/hr, 2 kg/m²/hr, 3 kg/m²/hr, 4 kg/m²/hr, 5 kg/m²/hr, 6 kg/m²/hr, 7kg/m²/hr, 8 kg/m²/hr, 9 kg/m²/hr, or at least about 10 kg/m²/hr. Amicro- or nanostructured membrane may permit a CO or CO₂ flux of no morethan about 10 kg/m²/hr, 9 kg/m²/hr, 8 kg/m²/hr, 7 kg/m²/hr, 6 kg/m²/hr,5 kg/m²/hr, 4 kg/m²/hr, 3 kg/m²/hr, 2 kg/m²/hr, 1 kg/m²/hr, 0.5kg/m²/hr, or about 0.1 kg/m²/hr or less.

A micro- or nanostructured membrane may be capable of permitting aparticular flux of hydrocarbons across the membrane. A flux ofhydrocarbons may be driven by a pressure gradient across the membrane.In some instances, a pressure gradient may be driven by a gas or liquidstream comprising hydrocarbons at a pressure elevated above ambientpressure. In other instances, a pressure gradient may exist by pulling avacuum on one side of the membrane, e.g. the lumen side. A micro- ornanostructured membrane may permit a hydrocarbon flux of about 0.1kilogram hydrocarbon/m² of membrane/hr (kg/m²/hr), 0.5 kg/m²/hr, 1kg/m²/hr, 2 kg/m²/hr, 3 kg/m²/hr, 4 kg/m²/hr, 5 kg/m²/hr, 6 kg/m²/hr, 7kg/m²/hr, 8 kg/m²/hr, 9 kg/m²/hr, or about 10 kg/m²/hr. A micro- ornanostructured membrane may permit a hydrocarbon flux of at least about0.1 kilogram kg/m²/hr, 0.5 kg/m²/hr, 1 kg/m²/hr, 2 kg/m²/hr, 3 kg/m²/hr,4 kg/m²/hr, 5 kg/m²/hr, 6 kg/m²/hr, 7 kg/m²/hr, 8 kg/m²/hr, 9 kg/m²/hr,or at least about 10 kg/m²/hr. A micro- or nanostructured membrane maypermit a hydrocarbon flux of no more than about 10 kg/m²/hr, 9 kg/m²/hr,8 kg/m²/hr, 7 kg/m²/hr, 6 kg/m²/hr, 5 kg/m²/hr, 4 kg/m²/hr, 3 kg/m²/hr,2 kg/m²/hr, 1 kg/m²/hr, 0.5 kg/m²/hr, or about 0.1 kg/m²/hr or less.

A membrane with an enhanced selectivity for one or more chemical speciesmay enhance the chemical conversion rate or phase equilibrium of aconversion system. Without wanting to be bound to theory, selectiveenrichment for one or more chemical species within the void or porespace of the micro- or nanostructured component of a membrane mayincrease the volumetric concentration of the one or more chemicalspecies within the void or pore space. In some instances, a kinetic rateenhancement or shift in phase equilibrium for a particular chemicalreaction may be driven by one or more chemical species having highervolumetric concentrations within the membrane than may be predicted bytheir bulk phase concentrations on either side of the membrane. In aparticular instance, the selective mass transfer of one or more chemicalspecies through a membrane may cause an increased concentration of theone or more chemical species in a boundary layer adjacent to the surfaceof the membrane. An increase in the boundary layer concentration of theone or more chemical species may increase the availability of one ormore chemical species to a catalyst deposited at the surface of themembrane. In another instance, a catalyst may be deposited within thevoid or pore space of a micro- or nanostructured material within amembrane, allowing direct transfer of an increased mass transfer of oneor more chemical species to the catalyst by bulk flow.

The mass transfer selectivity of a membrane for one or more chemicalspecies may cause a measurable enhancement of the rate of reaction forone or more chemical reactions in a chemical conversion system thatcomprises such a membrane. In some instances, the rate of reaction forone or more chemical reactions may increase by at least about 5%, 10%,20%, 30%, 40%, 50%, 75%, 100%, 150%, 200%, 500%, or about 1000% or more.In some instances, the rate of reaction for one or more chemicalreactions may be higher than may be predicted by the use of measuredreactant concentrations due to other synergistic effects such aselectric field enhancement of catalyst activity. In some instances, themass transfer selectivity of a membrane for one or more chemical speciesmay cause a measurable reduction in the rate of reaction for one or morechemical unwanted reactions (e.g. side reactions, degradation reactions)in a chemical conversion system that comprises such a membrane. In someinstances, the rate of reaction for one or more unwanted chemicalreactions may decrease by at least about 5%, 10%, 20%, 30%, 40%, 50%,75%, 100%, 150%, 200%, 500%, or about 1000% or more.

A membrane comprising a micro- or nanostructured material may furthercomprise one or more catalyst materials. A catalyst material may beattached, bonded, deposited or functionalized to the surface of a micro-or nanostructured material. In some instances, a catalyst may be locatedon a surface of a membrane. A catalyst may be localized in particularareas of a membrane or on particular areas of a micro- or nanostructuredmaterial to control where a catalyzed chemical reaction may occur. Acatalyst may be located within a pore or pore-like structure in amembrane. A chemical reaction catalyzed by a catalyst may occur on aparticular area of the membrane or within the pore or pore-like space ofthe membrane. A catalyst may comprise a metal atom, metal complex, ormetal particle. A catalyst may comprise a metal such as titanium,vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,aluminum, silicon, yttrium, zirconium, niobium, molybdenum, ruthenium,rhodium, palladium, silver, cadmium, indium, tin, antimony, tantalum,tungsten, osmium, platinum, gold, mercury, or lead. In some instances, adoped carbon nanomaterial may comprise a catalyst. In a particularinstance, N-doped carbon nanotubes may comprise a catalyst. In anotherinstance, carbon nanotubes with electrodeposited platinum, nickel, orcopper nanoparticles may comprise a catalyst (see FIG. 5 ). A membranemay comprise more than one catalyst. In some instances, one or morecatalysts may be deposited on one or more areas or surfaces of amembrane, and one or more differing catalysts may be deposited on one ormore differing areas or surfaces of a membrane. A membrane may becapable of catalyzing one or more chemical reactions when mass transferoccurs in a particular direction across the membrane, and may be capableof catalyzing one or more differing chemical reactions when masstransfer occurs in a differing direction across the membrane.

An electrochemical reduction process utilizing a micro- ornanostructured catalyst membrane may utilize methods or components tominimize catalyst poisoning. A micro- or nanostructured membranecomprising a catalyst may be refreshed or regenerated to mitigate theimpact of catalyst poisoning and the deposition of other unwantedspecies. In some instances, a membrane may be removed from anelectrochemical reduction system for catalyst regeneration. In otherinstances, a membrane may be flushed with acid to dissolve or removecatalyst particles, followed thereafter by deposition of new catalystparticles on the membrane surface or nanoparticle surface.

A membrane comprising a micro- or nanostructured material may haveenhanced electrical properties. In some aspects, the membranes may beconductive, due to the electrical properties of the micro- ornanostructured materials. In some instances, a membrane may besemiconducting (e.g. carbon nanotubes of a particular chirality). Amembrane may be configured to act as an electrode in an electrochemicalsystem. A membrane may allow an electrical current to be conveyed to oneor more catalysts associated with it. An electrical current may enhancethe reactivity of a catalyst for particular catalyzed chemicalreactions. In some instances, the selective mass transfer of particularchemical species across a micro- or nanostructured membrane may increasethe current density achieved at the membrane electrode.

A membrane comprising a micro- or nanostructured material may beutilized for various purposes. In some instances, a membrane may permitmass transfer of a chemical species from a first gas mixture into asecond gas mixture. In some instances, a membrane may permit masstransfer of a chemical species from a gas phase into a liquid phase. Insome instances, a membrane may permit mass transfer of a chemicalspecies from a first liquid mixture into a second liquid mixture. Insome instances, a membrane may permit mass transfer of a chemicalspecies to a catalytic site where a chemical reaction may occur. In someinstances, a membrane may be utilized to perform both chemicalseparations and catalysis. In some instances, a membrane may be cycledbetween separation and catalysis by the directional application ofelectric fields or other fields or forces. In other instances, amembrane may be capable of simultaneously catalyzing and performing achemical separation.

Chemical Conversion Systems

The invention of the present disclosure includes chemical conversionsystems for the conversion of carbon dioxide into other chemical species(e.g., C1+ products) via electrochemical reduction. Numerous embodimentsof the present invention may be conceived over a wide range ofprocessing scales. CO or CO₂ conversion systems may include microscalefuel production devices, standalone chemical production systems thatproduce specific chemicals or fuels at the scale of tens to hundreds ofkilograms per day, or industrial-scale production of chemicals or fuelsat the scale of thousands of kilograms per day or more.

A chemical conversion system may utilize one or more micro- ornanostructured membranes to perform the electrochemical reduction ofcarbon dioxide. A chemical conversion system may include one or moremicro- or nanostructured membranes to perform a separation of carbondioxide from a gas stream and supply the carbon dioxide to a chemicalreactor. A chemical conversion system may include one or more micro- ornanostructured membranes to perform a separation of a chemical mixtureresulting from a unit operation of a chemical conversion system. Achemical conversion system may include one or more micro- ornanostructured membranes to perform a catalyzed electrochemicalreduction of carbon dioxide to another chemical species (e.g. formate,methanol, ethanol). A chemical conversion system may include one or moremicro- or nanostructured membranes to perform one or more catalyzedconversion reactions of one or more species formed via electrochemicalreduction of carbon dioxide (e.g. further reduction of CO or CO₂ reducedproducts, such as formate to methanol or ethanol, methanol and ethanolto propanol, ethanol to butanol, etc; dehydration of ethanol toethylene).

A chemical conversion system may comprise one or more unit operationsfor separating chemical species using a membrane comprising a micro- ornanostructured material. A chemical conversion system may comprise oneor more unit operations for reacting one or more chemical species usinga membrane comprising a micro- or nanostructured material. In someinstances, a chemical conversion system may utilize micro- ornanostructured membrane unit operations for distinct operations, such asthe reaction of one or more chemical species or the separation of one ormore chemical species. In some instances, a chemical conversion systemmay utilize a single micro- or nanostructured membrane unit operationfor multiple operations, such as simultaneous reaction and separation ofone or more chemical species. In some instances, a chemical conversionsystem may comprise a plurality of unit operations comprising a membranethat comprises a micro- or nanostructured material. In some instances, aplurality of unit operations may be working redundantly on a particularprocess, for example multiple CO or CO₂ to formate chemical reactors. Inother instances, a plurality of unit operations may be performing arange of processes, for example chemical reactors tailored to producehydrocarbons with varying molecular weight ranges.

Any unit operation in a chemical conversion system may be designed tooperate in a batch, semi-batch, or continuous mode. Any unit operationin a chemical conversion system may have one or more feed streams. Anyunit operation in a chemical conversion system may have one or moreproduct streams. A unit operation in a chemical conversion system mayutilize one or more recycle or purge streams to control its function. Insome instances, a unit operation capable of multiple processes (e.g.reaction and separation) may operate continuously. In some instances, aunit operation capable of multiple processes may operate cyclicallybetween modes of operation.

A chemical conversion system of the present invention may comprise anynumber of additional operations beyond the membrane-based unitoperations. A chemical conversion system may comprise one or more unitoperations for separations. Separation unit operations may includedistillation columns, reactive distillation columns, gas absorptioncolumns, stripping columns, additional catalysis operations, such aswith catalyst packed columns, flash tanks, humidifiers, leaching units,liquid-liquid extraction units, dryers, adsorption systems, ion-exchangecolumns, membrane separation units, filtration units, sedimentationunits, and crystallization units. A chemical conversion system maycomprise one or more unit operations for heat transfer. Heat transferunit operations may include mantle heaters, cartridge heaters, tapeheaters, pad heaters, resistive heaters, radiative heaters, fan heaters,shell-and-tube heat exchangers, plate-type heat exchangers,extended-surface heat exchangers, scraped-surface heat exchangers,condensers, vaporizers, and evaporators. A chemical conversion systemmay comprise one or more unit operations for fluid transfer. Fluidtransfer devices may include piping, tubing, fittings, valves, pumps,fans, blowers, compressors, stirrers, agitators, and blenders. Pumpingequipment may be operated at pressures above atmospheric pressure orused to draw a vacuum. A chemical conversion system may comprise one ormore chemical reaction units aside from an electrochemical reductionreactor. Chemical reaction units may include plug flow reactors,continuous-stirred tank reactors, packed bed columns, fluidized bedreactors, and batch reactors. Chemical reactors may be utilized forvarious upgrading and conversions including dehydrogenation,hydrogenation, cracking, dehydration, decarboxylation, carboxylation,amination, deamination, alkylation, dealkylation, oxidation, reduction,polymerization, and depolymerization.

A chemical conversion system may have one or more pieces of equipmentfor process control or process safety. A chemical conversion system maycontain one or more thermocouples, temperature gauges, pressure gauges,rotameters, mass flow controllers, pH probes, chemical analyzers,velocity gauges, infrared sensors, flow sensors, PID control devices,PLC control devices, purge valves, purge lines, and recycle lines. Achemical conversion system may be under operative control by one or morecomputers or computer systems.

Any unit operation within a chemical conversion system, including acentral electrochemical reduction unit, may have at least one feed orinput stream. Any unit operation within a chemical conversion system,including a central electrochemical reduction unit, may have at leastone product or outlet stream. Any feed or input stream and product oroutlet stream may comprise one or more inline unit operations forprocesses such as fluid transfer, heat transfer, mass transfer, chemicalreaction, or process control.

A chemical conversion system comprising one or more micro- ornanostructured membranes may reduce or eliminate the energy consumptionassociated with one or more unit operations. For example, a gasseparator comprising one or more micro- or nanostructured membranes mayeliminate the need for a distillation column or separate adsorptionsystem to separate CO or CO₂ from air. In some instances, theutilization of unit operations comprising micro- or nanostructuredmembranes may eliminate one or more pumps, compressors, heat exchangers,separators, or reactors from an electrochemical reduction system. Theutilization of one or more micro- or nanostructured membranes may reducethe energy consumption of a processing step or processing component byat least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99% or more.

A chemical conversion system may comprise one or more energy generationdevices. Energy generation devices may comprise renewable or cleanenergy generation devices such as photovoltaic cells, solarconcentration heaters, wind turbines, water turbines, biomass combustionsystems, and biomass gasifiers. A chemical conversion system may be indirect electrical connection with an energy source such as a nuclearpower source or a geothermal power source. A renewable or clean energysource may provide the electrical energy source necessary toelectrochemically reduce CO or CO₂ to other chemicals. A renewable orclean energy source may provide the electrical energy source necessaryto perform any other unit operation necessary to produce a chemicalproduct. A renewable or clean energy source may include solar powersources (e.g. photovoltaic cells) geothermal power sources,hydroelectric power sources, nuclear power sources, tidal power sources,wind power sources, biomass power sources, or any combination thereof.In some instances, a chemical conversion system may be entirelyself-sustaining, i.e. no external power supply is necessary. In otherinstances, a chemical conversion system may reduce the external powerdemand of a chemical production process when compared to a conventionalproduction method. In some cases, power generation systems may beemployed to make use of non-target byproducts, such as with a fuel cellfor conversion of hydrogen, methane, or CO with oxygen to createelectricity, which may be used in the electrochemical process.

A chemical conversion system may reduce the external power demand of achemical process by at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%,98%, 99% or more. In some instances, a chemical conversion system maygenerate fuels with a greater energy content than the total externalenergy consumed to produce the fuels. A chemical conversion system mayreduce the carbon footprint for the production of one or more chemicals.

A chemical conversion system may reduce the net carbon emissions of achemical production process. The total carbon emissions of a chemicalproduction process may decrease by at least about 5%, 10%, 15%, 20%,25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%,95%, 96%, 97%, 98%, 99% or more. In some instances, a chemicalproduction process may be net carbon negative, i.e. more carbon issequestered in a product than is released by the production of theproduct. A chemical conversion system may be utilized to reduce the netcarbon emissions of another chemical process. In some instances, achemical conversion system may be coupled to an effluent gas source(e.g. a power plant flue gas stream) to minimize the total carbondioxide release from the effluent gas source. A chemical conversionsystem may reduce the total carbon emissions of another system or sourceby at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more.

Chemical Reduction Systems and Methods

The present disclosure provides chemical conversion systems that convertCO or CO₂ to other chemicals (e.g., C1+ products) via an electrochemicalreduction system. In some instances, the electrochemical conversionssystem may produce hydrocarbons in the liquid phase via theelectrochemical reduction of bicarbonate ions that are produced by thereaction of CO or CO₂ with water. The electrochemical reduction systemmay generate bicarbonate ions via the capture of CO or CO₂ from varioussources, including atmospheric carbon dioxide and effluent gases from anindustrial or chemical process. In some instances, the chemicalreduction system may reduce the energy consumption of a CO or CO₂reduction process by at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%,98%, 99% or more. In some instances, a CO or CO₂ reduction system mayutilize a feed stream comprising carbon dioxide without the need forfurther purification. In some instances, a CO or CO₂ reduction systemmay utilize a feed stream comprising CO or CO₂ without the need foradditional separation processes that enrich the CO or CO₂ composition ofthe feed stream. A feed stream to an electrochemical reduction systemmay comprise carbon dioxide on a molar basis of about 0.01%, 0.02%,0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.5%, 1%, 5%, 10%,20%, 50%, 90%, 95% or more. A feed stream to an electrochemicalreduction system may comprise carbon dioxide on a molar basis of atleast about 0.01%, 0.02%, 0.03%, 0.04%, 0.06%, 0.07%, 0.08%, 0.09%,0.1%, 0.2%, 0.5%, 1%, 5%, 10%, 20%, 50%, 90%, 95% or more. A feed streamto an electrochemical reduction system may comprise carbon dioxide on amolar basis of no more than about 95%, 90%, 50%, 20%, 10%, 5%, 1%, 0.5%,0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, or 0.01%or less.

An electrochemical reduction system may produce hydrocarbons at aspecific rate based upon the available surface area for electrochemicalreduction. An electrochemical reduction system may produce hydrocarbonsat a rate of about 10 kilograms/meter squared/hour (kg/m²/hr), 20kg/m²/hr, 30 kg/m²/hr, 40 kg/m²/hr, 50 kg/m²/hr, 60 kg/m²/hr, 70kg/m²/hr, 80 kg/m²/hr, 90 kg/m²/hr, 100 kg/m²/hr, 150 kg/m²/hr, or about200 kg/m²/hr. An electrochemical reduction system may producehydrocarbons at a rate of about 10 kg/m²/hr, kg/m²/hr, 30 kg/m²/hr, 40kg/m²/hr, 50 kg/m²/hr, 60 kg/m²/hr, 70 kg/m²/hr, 80 kg/m²/hr, kg/m²/hr,100 kg/m²/hr, 150 kg/m²/hr, or about 200 kg/m²/hr or more. Anelectrochemical reduction system may produce hydrocarbons at a rate ofno more than about 200 kg/m²/hr, 150 kg/m²/hr, 100 kg/m²/hr, 90kg/m²/hr, 80 kg/m²/hr, 70 kg/m²/hr, 60 kg/m²/hr, 50 kg/m²/hr, kg/m²/hr,30 kg/m²/hr, 20 kg/m²/hr, or 10 kg/m²/hr or less.

An electrochemical reduction system may have a selectivity for theconversion of CO or CO₂ to one or more chemical species (e.g., C1+products). In some instances, a selectivity may be defined as thepercentage of carbon atoms entering a reactor, system, or unit that areconverted to a product species. For example, a selectivity of 50% mayindicate that 50% of entering CO or CO₂ molecules were converted to ahydrocarbon species in a reactor, system or unit. In some instances, aselectivity may be defined as the percentage of carbon atoms entering areactor, system, or unit that are converted to a chemical species withina particular class, weight range, carbon number range, or othercharacteristic. For example, a selectivity of 50% C1-C4 may indicatethat 50% of entering CO or CO₂ molecules were converted to a C1 to C4hydrocarbon product. A selectivity may be a single-pass selectivity. Asingle-pass selectivity may be defined as the percentage of carbon atomsentering a reactor, system, or unit that are converted to a hydrocarbonproduct on a single pass through the reactor, system, or unit. Aselectivity may be a recycled selectivity. A recycled selectivity may bedefined as the percentage of carbon atoms entering a reactor, system, orunit that are converted to a hydrocarbon product on two or more passesthrough the reactor, system, or unit.

An electrochemical reduction system may have a selectivity of about 10%,20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or about 99%. Anelectrochemical reduction system may have a selectivity of at leastabout 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or about 99% ormore. An electrochemical reduction system may have a selectivity of nomore than 99%, 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% orless.

An electrochemical reduction system for the conversion of CO or CO₂ intoother chemicals may comprise various components that may be necessaryfor the reduction of CO or CO₂. Components may include cathodes, anodes,contactors, extractors, pumps, vapor-liquid separators, and ion exchangemembranes. In some instances, some components may be included orexcluded from a chemical reduction system depending upon the preferredembodiment of the device. In some instances, a chemical reduction systemmay be a single, stand-alone, or fully integrated system that performsall processes in the electrochemical reduction of CO or CO₂. In otherinstances, an electrochemical reduction system may comprise at least twoor more operatively linked unit operations that collectively perform thenecessary processes in the electrochemical reduction of CO or CO₂.

An electrochemical reduction system may comprise a housing. The housingmay provide various functions to the electrochemical reduction system,including without limitation: securing components (e.g., membranes),physically containing fluids, separating differing fluids within asingle unit, retaining temperature or pressure, and/or providinginsulation. The housing may comprise any suitable material, includingmetals, ceramics, refractories, insulations, plastics, and glasses. Thehousing may comprise one unit of an electrochemical reduction system(e.g., a cathode). The housing may comprise two or more units of anelectrochemical reduction system (e.g., a cathode and anode). A completeelectrochemical reduction system may be contained within a singlehousing.

The housing may include one or more walls. The housing may include oneor more compartments or chambers. The housing may have a cross-sectionthat is circular, triangular, square, rectangular, pentagonal,hexagonal, or partial shapes or combinations of shapes thereof. Thehousing may be single-piece or formed of multiple pieces (e.g., pieceswelded together). The housing may include a coating on an interiorportion thereof. Such coating may prevent reaction with a surface in theinterior portion of the housing, such as corrosion or anoxidation/reduction reaction with the surface.

An electrochemical reduction system may comprise a cathode, an anode andan electrolyte solution that collectively provide the necessarycomponents for the reduction of carbon dioxide to other chemicalspecies. The electrolyte may comprise an aqueous salt solution that iscomposed with an optimal ionic strength and pH for the electrochemicalreduction of CO or CO₂. An electrolyte may comprise an aqueous saltsolution comprising bicarbonate ions. In some instances, an electrolytemay comprise an aqueous solution of sodium bicarbonate or potassiumbicarbonate. In some instances, bicarbonate ions may dissociate in thepresence of one or more catalysts to produce CO or CO₂ molecules for areduction reaction. The dissolution of CO or CO₂ into the electrolytesolution may regenerate or maintain the optimal concentration ofbicarbonate ions.

An electrochemical reduction system may be configured to operate at anoptimal processing temperature. An electrochemical reduction system orany component thereof may have an operating temperature of about −30°C., −20° C., −10° C., 0° C., 5° C., 10° C., 15° C., 20° C., 30° C., 35°C., 40° C., 50° C., 60° C., 70° C., or about 80° C. An electrochemicalreduction system or any component thereof may have an operatingtemperature of at least about −30° C., −20° C., −10° C., 0° C., 5° C.,10° C., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 50° C., 60° C.,70° C., or about 80° C. or more. An electrochemical reduction system orany component thereof may have an operating temperature of no more thanabout 80° C., 75° C., 70° C., 65° C., 60° C., 55° C., 45° C., 40° C.,35° C., 30° C., 25° C., 20° C., 15° C., 10° C., 5° C., 0° C., −5° C.,−10° C., −20° C., or about −30° C. or less.

An electrochemical reduction system may be configured to operate at anoptimal voltage for the reduction of CO or CO₂ to reduced products. Anelectrochemical reduction system may be arranged in a stack or seriesconfiguration to tailor the system voltage to an optimal value. Anelectrochemical reduction system may have an operating voltage of aboutvolts (V), 0.2V, 0.3V, 0.4V, 0.5V, 0.75V, 1.0V, 2.0V, 3.0V, 4.0V, 5.0V,10 V, 15V, or about 20V. An electrochemical reduction system may have anoperating voltage of at least about 0.1 volts (V), 0.2V, 0.3V, 0.4V,0.5V, 0.75V, 1.0V, 2.0V, 3.0V, 4.0V, 5.0V, 10 V, or about 20V or more.An electrochemical reduction system may have an operating voltage of nomore than about 20V, 15V, 10V, 5.0V, 4.0V, 3.0V, 2.0V, 1.0V, 0.75V,0.5V, 0.3V, 0.2V, or about 0.1V or less.

An electrochemical reduction system may have an optimal cathode currentdensity. In some instances, the cathode current density may determinethe rate of CO or CO₂ reduction at the cathode. A cathode may becharacterized by an overall electrochemical efficiency. An overallelectrochemical efficiency may be defined as the percentage ofelectrical energy converted into chemical energy. A cathode may have acathode current density of about 10 milliAmps/square centimeter(mA/cm²), 50 mA/cm², 100 mA/cm², 150 mA/cm², 200 mA/cm², 250 mA/cm², 300mA/cm², 350 mA/cm², 400 mA/cm², 450 mA/cm², 500 mA/cm², 600 mA/cm², 700mA/cm², 800 mA/cm², 900 mA/cm², or about 1000 mA/cm². A cathode may havea cathode current density of at least about 10 mA/cm², 50 mA/cm², 100mA/cm², 150 mA/cm², 200 mA/cm², 250 mA/cm², 300 mA/cm², 350 mA/cm², 400mA/cm², 450 mA/cm², 500 mA/cm², 600 mA/cm², 700 mA/cm², 800 mA/cm², 900mA/cm², or about 1000 mA/cm 2 or more. A cathode may have a cathodecurrent density of no more than about 1000 mA/cm², 900 mA/cm², 800mA/cm², 700 mA/cm², 600 mA/cm², 500 mA/cm², 450 mA/cm², 400 mA/cm², 350mA/cm², 300 mA/cm², 250 mA/cm², 200 mA/cm², 150 mA/cm², 100 mA/cm², 50mA/cm², 10 mA/cm 2 or less.

A cathode in an electrochemical reduction system may have an overallelectrochemical efficiency. A cathode may have an overallelectrochemical efficiency of about 5%, 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more. Acathode may have an overall electrochemical efficiency of at least about5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, 95% or more. A cathode may have an overallelectrochemical efficiency of no more than about 95%, 90%, 85%, 80%,75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%or less.

An electrolyte may comprise a solution with a particular ionic strengthor molarity. An electrolyte may have an ionic strength of about 0.01moles/liter (M), 0.05M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M, 0.9M,1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 2.0M, 2.5M, or about 3.0M. Anelectrolyte may have an ionic strength of at least about 0.05M, 0.1M,0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M, 0.9M, 1.0M, 1.1M, 1.2M, 1.3M,1.4M, 1.5M, 2.0M, 2.5M, or at least about 3.0M or more. An electrolytemay have an ionic strength of no more than about 3.0M, 2.5M 2.0M, 1.5M,1.4M, 1.3M, 1.2M, 1.1M, 1.0M, 0.9M, 0.8M, 0.7M, 0.6M, 0.5M, 0.4M, 0.3M,0.2M, 0.1M, 0.05M, or no more than about 0.01M or less. A salt in anelectrolyte may have a molarity of about (M), 0.05M, 0.1M, 0.2M, 0.3M,0.4M, 0.5M, 0.6M, 0.7M, 0.8M, 0.9M, 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M,2.0M, 2.5M, or about 3.0M. A salt in an electrolyte may have a molarityof at least about 0.01M, 0.05M, 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M,0.8M, 0.9M, 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 2.0M, 2.5M, or at leastabout 3.0M or more. A salt in an electrolyte may have a molarity of nomore than about 3.0M, 2.5M 2.0M, 1.5M, 1.4M, 1.3M, 1.2M, 1.1M, 1.0M,0.9M, 0.8M, 0.7M, 0.6M, 0.5M, 0.4M, 0.2M, 0.1M, 0.05M, or no more thanabout 0.01M or less. A salt in an electrolyte may have a molarity in arange from about 0.01M to about 0.1M, about 0.01M to about 0.2M, about0.01M to about 0.5M, about 0.01M to about 1.0M, about 0.01M to about3.0M, about to about 0.2M, about 0.1M to about 0.5M, about 0.1M to about1.0M, about 0.1M to about 3.0M, about 0.2M to about 0.5M, about 0.2M toabout 1.0M, about 0.2M to about 3.0M, about 0.5M to about 1.0M, about0.5M to about 3.0M, or about 1.0M to about 3.0M.

An electrolyte may have an optimal pH for the electrochemical reductionof CO₂. An electrolyte may have a pH of about 0, 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, or about 14. An electrolyte may have a pH of at leastabout 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or more. Anelectrolyte may have a pH of no more than about 14, 13, 12, 11, 10, 9,8, 7, 6, 5, 4, 3, 2, 1, 0 or less. An electrolyte may have a pH in arange from about 0 to about 2, about 0 to about 3, about 0 to about 4,about 0 to about 5, about 0 to about 7, about 0 to about 10, about toabout 14, about 2 to about 3, about 2 to about 4, about 2 to about 5,about 2 to about 7, about 2 to about 10, about 2 to about 14, about 3 toabout 4, about 3 to about 5, about 3 to about 7, about 3 to about 10,about 3 to about 14, about 4 to about 5, about 4 to about 7, about 4 toabout 10, about 4 to about 14, about 5 to about 7, about 5 to about 10,about 5 to about 14, about 7 to about 10, about 7 to about 14, or fromabout 10 to about 14.

An electrolyte in an electrochemical reduction system may be anon-aqueous electrolyte. In some instances, an electrolyte may comprisean ionic liquid with a dissolved salt. An ionic liquid may include, butis not limited to, 34midazolium-based fluorinated anion ionic liquids,34midazolium acetates, 34midazolium fluoroacetates, pyrrolidinium ionicliquids, or any combination thereof.

An anode may comprise an elemental metal such as nickel, tin, or gold.An anode may comprise a wire mesh, metal foam or other permeablestructure of the chosen anode material. An anode material may be inoperative contact with an anion exchange membrane material or anotherphysical separator that prevents contact with the cathode.

A cathode may comprise any appropriate material. In some instances, acathode may comprise copper nanoparticles and/or N-doped carbonnanomaterials. In some instances, a cathode may comprise a micro- ornanostructured membrane material. In some instances, a cathode maycomprise one or more catalysts for the electrochemical reduction of COor CO₂ or other chemical reactions. A cathode material may be inoperative contact with an anion exchange membrane material or anotherphysical separator that prevents contact with the cathode. In someinstances, the distance between the cathode and anode may be minimizedto reduce resistance. In some instances, forced convective flow ofelectrolyte between the electrodes may further reduce electricalresistance and/or may allow for greater distance between the electrodes.In some instances, the electrodes may be in different housings. In someinstances, the anode and cathode may have a minimal distance with an ionselective membrane between them. In some instances, no ion selectivemembrane may be used.

An electrochemical reduction system may comprise one or more extractorunits. An extractor unit may comprise any unit operation or separationunit that selectively separates one or more chemical species from a feedstream. In some instances, an extractor may comprise a membraneseparator. In some instances, an extractor may comprise a micro- ornanostructured membrane. In some instances, an extractor may extract oneor more chemical species derived from the reduction of carbon dioxide.In some instances, an extractor may extract one or more chemical speciesderived from the reduction of CO or CO₂ from an electrolyte solution. Inother instances, an extractor may separate one or more chemical speciesderived from the subsequent reaction of carbon dioxide electrochemicalreduction products.

An electrochemical reduction system may comprise one or more contactorunits. A contactor unit may comprise any unit operation or separationunit that selectively separates one or more chemical species from a feedstream. In some instances, a contactor may comprise a gas adsorptioncolumn. In other instances, a contactor may comprise packing to increasea liquid solutions surface area and a fan to increase gas passage at theliquid interface. Such contactors may share design features with coolingtowers. In other instances, an extractor may comprise a membraneseparator. In some instances, an extractor may comprise a micro- ornanostructured membrane. In some instances, a contactor may extract oneor more chemical species from a feed stream. In some instances, acontactor may extract carbon dioxide from a feed stream. In someinstances, a contactor may separate CO or CO₂ from a feed stream anddissolve the CO or CO₂ in an electrolyte solution. In some cases, a feedstream may be air. In some cases, the feed stream may be filtered priorto use. Such filtering may in some cases remove particulate matterand/or volatile organic materials and/or undesired materials of variouskinds. The uptake of CO or CO₂ in a gas contactor may be enhanced by thepresence of hydroxide ions generated within the electrochemicalreduction system.

An electrochemical reduction system may comprise one or more ionexchange membranes. An ion exchange membrane may comprise a cationexchange membrane, an anion exchange membrane, or a bipolar membrane. Anion exchange membrane may be in operative contact with a cathode, ananode, or both a cathode and anode. In some instances, anelectrochemical reduction system may comprise no ion exchange membranes.In some instances, an ion exchange membrane may be configured tominimize the distance between the anode and the cathode. An ion exchangemembrane may have a thickness of about 1 μm, μm, 10 μm, 25 μm, 50 μm,100 μm, 125 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, 750 μm,1 mm, or more than 1 mm. An ion exchange membrane may have a thicknessof at least about 1 μm, 5 μm, 10 μm, 25 μm, 50 μm, 100 μm, 125 μm, 150μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, 750 μm, 1 millimeter (mm),or more. An ion exchange membrane may have a thickness of no more thanabout 1 mm, 750 μm, 500 μm, 400 μm, 300 μm, 250 μm, 200 μm, 150 μm, 125μm, 100 μm, 50 μm, 25 μm, 10 μm, 5 μm, 1 μm, or less.

An electrochemical reduction system may comprise one or morecompartments or chambers. Compartments or chambers may be defined asenclosed volumes within the electrochemical reduction system where masstransfer occurs. For example, an electrochemical reduction system maycomprise a first compartment or chamber where a C1+ product is produced,and a second compartment or chamber where C1+ product is extracted,separated, or otherwise transferred from the first compartment. FIGS.16A-16C show various exemplary configurations of compartments orchambers within the scope of the present invention. FIG. 16A depicts aschematic view of an electrochemical reduction system 1000 where thefirst compartment or chamber 100 comprises a cathode 140 and the secondcompartment or chamber 200 comprise an anode 160, where the anode 140and cathode 160 are electrically coupled by a voltage source 130. Thefirst compartment or chamber 100 is separated from the secondcompartment or chamber 200 by a micro- or nanostructured membrane 150,which controls the transfer of C1+ product from the first compartment orchamber 100 to the second compartment or chamber 200. FIG. 16B depicts aschematic view of an electrochemical reduction system 1000 containing acathode unit 210 and an anode unit 220. The cathode unit 210 comprises afirst compartment or chamber 100 containing the cathode 140 that iselectrically coupled by a voltage source 130 to an anode 160 in theanode unit 220. The first compartment or chamber 100 is separated from asecond compartment or chamber 200 by a micro- or nanostructured membrane150, which controls the transfer of C1+ product from the firstcompartment 100 to the second compartment or chamber 200 within thecathode unit 210. FIG. 16C depicts a schematic view of anelectrochemical reduction system 1000 comprising a cathode unit 210, ananode unit 220, and an extractor 230. The cathode unit comprises acathode 140 and a first compartment 100. The cathode 140 is electricallycoupled to the anode 160 in the anode unit 220 by a voltage source 130.A C1+ product is produced in the first compartment or chamber of thecathode unit 210 and is transferred by stream C1+ to the extractor,which comprises a second compartment or chamber 200. The C1+ product istransferred from stream C1+ into the second compartment or chamber 200by passage through a micro- or nanostructured membrane 150.

Various embodiments of chemical reduction systems utilizing micro- ornanostructured membranes may be conceived. In an embodiment, depicted inFIG. 6 , an electrolyte solution with an optimal pH (1) may beintroduced to a chemical reduction unit (2), where CO₂ is introduced tothe electrolyte and reduced by a catalyst to useful reduced carbonproducts (RCPs). In some instances, CO₂ is captured in a separate unitoperation and introduced into the chemical reduction unit as a gas. Insome instances, CO₂ is captured in a separate unit operation andintroduced as a component of the electrolyte. In some instances, thechemical reduction unit may consist of various housings, tanks, pumps,or other elements used to operate the unit. In some cases, separatecatholyte and anolyte reservoirs may be used. In some cases, pumping maybe used to circulate catholyte and anolyte to an electrolysis stack. Insome instances, the catholyte reservoir may also be a vapor liquidseparator. In some instances, heat exchangers and cooling or heatingsystems may be used to maintain desired temperatures in the variousreservoirs, stack, or other unit elements. In some instances, thechemical reduction unit (2) may comprise a micro- or nanostructuredmembrane. The micro- or nanostructured membrane may comprise one or morecatalysts. In other instances, a catalysis process may comprise aconventional electrochemical “stack”, comprising an anode and cathodewithin the same housing. In some instances, an ion exchange membrane maybe used. In some instances, various catalytic membranes may be used, orotherwise achieve the desired reduction of CO₂ by other methods ofreduction. Oxygen or other oxidized species may also be produced by sucha process and released to the atmosphere or directed to beneficial use.A stream containing RCPs (3) is directed to an extractor (4), where theRCPs are extracted. In some instances, the RCP stream is a liquidelectrolyte. In some instances, the RCP stream is a vapor. In someinstances, the RCP stream is a vapor collected from the gas space abovethe electrolyte. In some instances, the gas space is integral to thechemical reduction unit. In some cases, the gas space is part of a vaporliquid separator which may be in a separate casing. In some instances,the vapor liquid separator may also be the catholyte reservoir. In someinstances, the extractor may comprise a membrane extractor. A membraneextractor may comprise a micro- or nanostructured membrane material.RCPs may be extracted through the pores or channels of the micro- ornanostructured membrane due to pressure or chemical potentialdifferences (for example, as produced by a vacuum downstream of thelumen or backing side of the membrane), producing an RCP product stream(5) which is condensed or otherwise collected by a collector unit. Acollector unit may comprise a condenser. In some instance, a collectorunit may comprise a heat exchange condenser, an adsorption unit or othercapture processes. In other instances, the collector system may beunderstood to mean any of a variety of product capture and/or furtherprocessing steps, which may include, by way of non-limiting examples,condensation, adsorption, re-pressurization, further reactions (such asfurther catalysis for polymerization or other formation of longer chainhydrocarbons, etc). The collected RCPs may be directed to furtherprocesses or uses in stream (7). A stream of any non-condensable,non-collectable, or intentionally not collected gases (8) may berecompressed by a vacuum pump (9) and ejected to the environment orcollected for further usage in a product stream (10). In some cases,non-collected gases may include reduced matter such as H₂, CO, CH₄ orother gases, including alcohols. In some cases, non-collected gases maybe put to beneficial use. In some instances, beneficial use may includegeneration of electricity in a fuel cell or other unit operation, whichmay use O₂ generated by the chemical reduction process. In someinstances, non-collected gases may be used prior to a vacuum pump. Insome instances, non-collected gases may be sold or used to makesecondary products. After RCP extraction, the RCP containing stream,which may be substantially depleted of RCPs or may have a baselinerecirculated concentration of RCPs (as may be needed to optimize variousfeatures or operations of the process, such as, for example, extraction)is returned to the chemical reduction unit as a feed stream (1).

In another embodiment, depicted in FIG. 7 , an electrolyte solution (1)may be directed to a chemical reduction unit (2), where CO or CO₂ isreduced to RCPs. An electrolyte solution containing RCPs (3) is directedto an extractor (4), where the RCPs are extracted. In some instances,the extractor may employ a vapor liquid separator such that RCPs may beextracted from the vapor stream above the electrolyte. In someinstances, the extractor may comprise a membrane extractor. A membraneextractor may comprise a micro- or nanostructured membrane material.RCPs may be extracted through the pores or channels of the micro- ornanostructured membrane due to pressure or chemical potentialdifferences (for example, as produced by a vacuum downstream of thelumen or backing side of the membrane), producing an RCP product stream(5) which is condensed or otherwise collected by a collector unit. Acollector unit may comprise a condenser. In some instance, a collectorunit may comprise a heat exchange condenser, an adsorption unit or othercapture processes. In other instances, the collector system may beunderstood to mean any of a variety of product capture and/or furtherprocessing steps, which may include, by way of non-limiting examples,condensation, adsorption, re-pressurization, further reactions (such asfurther catalysis for polymerization or other formation of longer chainhydrocarbons, etc). The collected RCPs may be directed to furtherprocesses or uses in stream (7). A stream of any non-condensable orotherwise non-collectable gases (8) may be recompressed by a vacuum pump(9) and ejected to the environment or collected for further usage in aproduct stream (10). The electrolyte stream which may be either largelydepleted of RCPs or has some recirculating concentration thereof, isdirected to a contactor (12). The contactor may comprise a membrane forseparating one or more gases from a gas feed stream, or utilize anyother approach for contacting a gas with an electrolyte stream. Acontactor membrane may comprise a micro- or nanostructured membrane. Agas feed stream may comprise air, an effluent gas, or any other gasstream comprising CO or CO₂ (13). In some instances, the hydroxidesformed in the electrolyte in the chemical reduction unit may be theprimary adsorbing species in the electrolyte to capture CO or CO₂. Insome instances, the electrolyte stream in a contactor may have its pHcontrolled for optimal CO or CO₂ adsorption by the addition of hydroxidespecies, such as sodium hydroxide or potassium hydroxide. A CO or CO₂depleted air stream may be directed to an atmospheric purge of anotheruse. An electrolyte solution with the desired pH and concentration ofcarbonate species may be returned as a feed stream (1) for reuse in thechemical reduction system.

In another embodiment, depicted in FIG. 8 , an electrolyte stream isdirected to a cathode unit. In some instances, the cathode unit maycomprise a micro- or nanostructured membrane. In some instances, thecathode unit may comprise a micro- or nanostructured membrane comprisingnitrogen doped carbon nanomaterials with copper nanoparticles (which mayinclude further deposition of NCMs to the membrane surface during itsfabrication or thereafter to facilitate improved electrical conductivityor other characteristics). At the cathode unit, CO or CO₂ may be reducedto RCPs. The RCPS may be extracted by a membrane (through the membraneto the backing layer, or lumen) (2), producing an RCP product stream (3)which is collected in a condenser (4), and produced as an RCP productstream (5). Any non-condensable gases (6) may be recompressed by avacuum pump (7) to maintain system vacuum or otherwise processed, andejected to the environment or subsequently put to some other use (8).The cathode electrolyte outlet stream (9) is directed to a contactor(10), which may contact the electrolyte solution with air, an effluentgas, or any other gas stream comprising CO or CO₂ (11), allowing theelectrolyte to adsorb CO or CO₂. CO- or CO₂-depleted air is directed toan outlet stream (12). The electrolyte stream containing adsorbed CO orCO₂ (13) is directed to an anode unit (14). In some instances, the anodeunit is in the same housing as the cathode unit. In some instances, thedistance between the cathode and anode are minimized. In some cases, anion exchange membrane is used between the cathode and anode. An anodemay comprise a membrane. In some instances, an anode may comprise amicro- or nanostructured material that may be of any type, such as amembrane comprising a carbon nanomaterial with reduced nanoparticleplatinum or a similar catalyst (such as nickel, indium oxide or otherswith similar performance characteristics, for example). The electrolytesolution may be directed from one side of the membrane to the other toincrease mass transfer to the catalyst sites. Oxygen and hydrogen (inthe form of hydronium, lowering pH) may be produced in the anode unit,completing the electrocatalytic circuit. The anode unit and the cathodemay be electrically connected. In some instance, the anode and cathodeunits may be incorporated within a single chemical reduction unit. Ifany residual RCPs are in stream (13), they may be oxidized in the anodeunit. In some instances, it may be optimal to have some amount ofoxidized RCP species available in the post-anode electrolyte stream tooptimize system cost or performance. Electrolyte solution containingoxygen and any CO or CO₂ that may have been released by the lowering ofthe pH of the solution (15) may be directed to a vapor liquid separatorunit (VLS) (16), where gases are directed to stream (17), and liquids tostream (18). Liquids produced from a VLS unit may be directed back tothe cathode unit for reuse. In this and other embodiments in which ananode and contactor are present, the relative order of these twooperations is often interchangeable, in that the contactor may comebefore the anode, or after, as desired. If the contactor comes after theanode, oxygen release and CO or CO₂ capture may potentially be achievedin the same unit operation.

In another embodiment, depicted in FIG. 9 , an electrolyte solution (1)is directed to a cathode unit (2). In some instances, the cathode unitmay comprise a micro- or nanostructured membrane. In some instances, thecathode unit may comprise a micro- or nanostructured membrane comprisingnitrogen doped carbon nanomaterials with copper nanoparticles. Thecathode unit membrane may have an external electric field appliedaxially to the direction of water transport in the nanopores orchannels, such that RCPs are substantially rejected by the membrane,such that largely RCP-depleted electrolyte is directed to stream (3),and an electrolyte stream with an increased concentration of RCPs isproduced as stream (4). The RCP concentration of stream (4) may beincreased with a longer cathode membrane feed channel (removingelectrolyte solution while retaining RCPs which are continuouslyproduced at the membrane surface). The RCP containing electrolyte stream(4) may be directed to an extractor (5). In some instances, theextractor may comprise a membrane extractor. A membrane extractor maycomprise a micro- or nanostructured membrane material. RCPs may beextracted through the pores or channels of the micro- or nanostructuredmembrane due to pressure or chemical potential differences (for example,as produced by a vacuum downstream of the lumen or backing side of themembrane), producing an RCP product stream (5) which is condensed orotherwise collected by a collector unit, producing an RCP product stream(8). Any non-condensable gases (9) may be recompressed by a vacuum pump(10) to maintain system vacuum, or subjected to any other processingmethod, and ejected to the environment or subsequently put to somebeneficial use (11). The extractor electrolyte product stream (12) isdirected to an anode (13), where oxygen generation and pH reduction mayoccur. In some instances, the anode unit is in the same housing as thecathode unit. In some instances, the distance between the cathode andanode are minimized. In some cases, an ion exchange membrane is usedbetween the cathode and anode. An oxygen containing stream (14) may bedirected to a VLS (15), producing a gas outlet stream (16) and a liquidoutlet stream (17). The RCP-depleted electrolyte stream (3) may bedirected to a contactor (18), where it is contacted with air, andeffluent gas, or any other gas stream comprising CO₂ (19), causingadsorption of CO or CO₂ to the electrolyte, facilitated by the increasein pH that occurs during the CO or CO₂ reduction. CO or CO₂-reduced ordepleted air may be directed to an outlet stream (20). Electrolytesolution containing RCPs and adsorbed CO or CO₂ (21) may be combined ormixed with stream (17), forming an electrolyte stream (1) for reuse inthe cathode unit.

In another embodiment, shown in FIG. 10 , an electrolyte stream (1) isdirected to a cathode unit comprising a membrane (2). In some instances,the cathode may comprise a micro- or nanostructured membrane. A gas feedstream comprising CO or CO₂ (3) is introduced to the electrolyte fromthe back of the membrane, such that it may become readily available tothe catalyst at the membrane surface. The CO or CO₂ may be substantiallypure, and may be from a variety of sources, including capture from acombustion source, geothermal source, direct air capture, or othersources, as may be desired. An RCP-containing electrolyte stream (4) maybe directed to an extractor (5), where RCPs (6) are extracted to acollector (7) and produced as stream (8). Non-condensable gases (NCGs)(9) are directed to a vacuum pump (10) and directed to stream (11).Post-extractor electrolyte solution (12) may be directed to an anode(13). In some instances, the anode unit is in the same housing as thecathode unit. In some instances, the distance between the cathode andanode are minimized. In some cases, an ion exchange membrane is usedbetween the cathode and anode. Oxygen-containing solution (14) producedat the anode may be directed to a VLS (15), producing and outlet gasstream (16) and an outlet liquid stream (17), which may be recycled tothe cathode unit.

In another embodiment, shown in FIG. 11 , an electrolyte solution (1)may introduced to a cathode unit comprising a membrane from the back orlumen side. In some instances, the cathode unit membrane may comprise amicro- or nanostructured membrane. The electrolyte solution may flow toan active catalyst surface, where CO or CO₂ is reduced to RCPs. Highefficiency utilization of catalyst use may be expected by introducingreactants at an ideal pH directly to the catalyst site in this manner.The RCP-containing electrolyte stream (3) is directed to an extractor(4), where RCPs (5) are extracted to a collector (6), and produced as anRCP product stream (7). Non-condensable gases (NCGs) (8) are directed toa vacuum pump (9) and directed to an outlet stream (10). Post-extractorelectrolyte solution (11) is directed to an anode unit (12). In someinstances, the anode unit is in the same housing as the cathode unit. Insome instances, the distance between the cathode and anode areminimized. In some cases, an ion exchange membrane is used between thecathode and anode. Oxygen-containing solution that may be produced inthe anode unit (13) is directed to a VLS (14), producing a gas outletstream (15) and a liquid outlet stream (16), which becomes a recycledfeed stream (1) for reuse.

In another embodiment, shown in FIG. 12 , an electrolyte solutioncomprising CO or CO₂ (1) is directed to an extracting catalytic membrane(2), where RCPs may be produced. An RCP-containing electrolyte stream(3) may be directed to a condenser (4), and produced as an RCP productstream (5). NCGs (6) are directed to a vacuum pump (7) and become outletstream 8. A post-extractor electrolyte solution, which may be largelydepleted of RCPs or have a desired minimum recirculating concentrationof RCPs, is directed to an ion exchange membrane (10), to allow forexchange of either OH− anions (in the case of an anion exchangemembrane), or H+ ions (in the case of a proton (or cation) exchangemembrane), from stream (11) to equilibrate the pH as required for thecontinued operation of the catalysis circuit, and to protect RCPs instream (9) from oxidation that may be expected to occur in contact withthe anode or its immediate environment. An ion-exchanged electrolytestream may be directed to an anode unit (17). In some instances, theanode unit is in the same housing as the cathode unit. In someinstances, the distance between the cathode and anode are minimized. Insome cases, an ion exchange membrane is used between the cathode andanode. In some instances, the flows indicated are diffusive. In someinstances, the flows indicated are recirculating flows intended toassist in the reduction of boundary layers and improve mass transport.This configuration allows a high circulating concentration of RCPs, ifdesired, which may improve the RCP extraction and/or offer otherbenefits. The pH equilibrated stream (13) is directed to a contactor(14), where CO or CO₂ is adsorbed from air, an effluent gas, or anyother gas stream comprising CO or CO₂ (15). CO or CO₂ depleted air maybe directed to outlet stream (16). The reconstituted electrolyte stream(1) may be directed for reuse in the cathode unit. In the anode system,oxygen may be produced and pH may be reduced. Oxygen-containing solution(18) may be directed to a VLS (19), producing outlet product gases (20)and outlet liquids (21), which may be recycled as stream (11) for reuse.In this and other embodiments where both a contactor and an ion exchangemembrane are used, the relative order of these operations may bechanged, for example having the contactor prior to the ion exchange orvice versa, as may be beneficial to system optimization.

In another embodiment, shown in FIG. 13 , an electrolyte solution (1) isdirected to a cathode unit (2) where RCPs may be produced. In someinstances, the cathode unit may comprise a micro- or nanostructuredmembrane. In some instances, the cathode unit may comprise a catalystcomprising nitrogen doped carbon nanomaterials with coppernanoparticles. In some instances, the cathode unit may comprise a micro-or nanostructured membrane comprising nitrogen doped carbonnanomaterials with copper nanoparticles. An RCP bearing electrolytestream (3) is directed to an extractor (4). A substantially purified RCPstream (5) is directed to a collector, producing a product stream (7).NCGs or other non-collected substances (8) are directed to a subsequentseparation unit(s) or process, such as a vacuum pump (9), becomingoutlet stream (10). Post-extractor electrolyte solution (11) is directedto an ion exchange (IX) membrane (12), where pH is equilibrated betweenstreams (11) and (13), producing electrolyte streams (14) (cathodeside), and (15) (anode side). Stream (15) is directed to an anode unit(16) that may produce an oxidized species-rich stream (17), which isdirected to a separator device (here denoted VLS) (18), separating theoxidized species from the electrolyte stream (20), which is reused asstream (13). Stream (14) is directed to a contactor, where it iscontacted with a CO or CO₂ source (22), resulting in a CO or CO₂depleted outlet stream (23), and an electrolyte stream with desiredcharacteristics (24) for recycle to the cathode unit. In some instances,the anode unit is in the same casing as the cathode unit. In someinstances, the distance between the cathode and anode are minimized. Insome cases, an ion exchange membrane is used between the cathode andanode. In some instances, the flows indicated are diffusive. In someinstances, the flows indicated are recirculating flows intended toassist in the reduction of boundary layers and improve mass transport.

In another embodiment, shown in FIG. 14 , an electrolyte solution (1) isdirected to a cathode unit (2) where RCPs may be produced. In someinstances, the cathode unit may comprise a micro- or nanostructuredmembrane. In some instances, the cathode unit may comprise a micro- ornanostructured membrane comprising nitrogen doped carbon nanomaterialswith copper nanoparticles. An RCP containing electrolyte stream (3) maybe directed to an extractor (4). A substantially-purified RCP stream (5)may be directed to a collector (6), producing an RCP product stream (7).NCGs or other non-collected substances (8) may be directed to asubsequent separation unit(s) or process, such as a vacuum pump (9),becoming outlet stream (10). A post-extractor electrolyte stream (11)may be directed to an ion exchange (IX) membrane (12), where pH may beequilibrated between streams (11) and (13), producing streams (14)(cathode side), and (15) (anode side). Stream (15) may be directed to ananode unit (16), producing oxidized species rich stream (17), which maybe directed to a separator device (here denoted VLS) (18), separatingthe oxidized species from the electrolyte stream (20), which may bereused as stream (13). Stream (14) becomes an electrolyte stream withdesired characteristics (14) for reuse. A CO or CO₂ source (21), whichmay be substantially pure, may be introduced to the cathode membranesuch that it is introduced to the active catalytic sites from thebacking or lumen side of a membrane, which may result in a highavailability and efficient utilization of the reactant at the catalystsites. In some instances, the anode unit is in the same housing as thecathode unit. In some instances, the distance between the cathode andanode are minimized. In some cases, an ion exchange membrane is usedbetween the cathode and anode. In some instances, the flows indicatedare diffusive. In some instances, the flows indicated are recirculatingflows intended to assist in the reduction of boundary layers and improvemass transport.

It shall be understood that the systems and processes for any describedembodiment of the chemical reduction system may be utilized in any otherembodiment of the chemical reduction system. For example, a particularcathode, anode, collector, extractor, contactor or vapor-liquid systemmay be applied to any embodiment of the chemical reduction system whenappropriate. In some instances, the differences in system configurationfor various embodiments may favor the selection of differing systemcomponents to produce optimal system performance and processingconditions.

Computer Systems

The present disclosure provides computer systems that are programmed toimplement methods of the disclosure. FIG. 15 shows a computer controlsystem 1501 that is programmed or otherwise configured to control achemical reduction system or a process within a chemical reductionsystem (e.g. controlling and balancing the pH of an electrolyte stream).The computer control system 1501 can regulate various aspects of themethods of the present disclosure, such as, for example, methods ofproducing a reduced carbon product or monitoring for potentiallyhazardous operating conditions. The computer control system 1501 can beimplemented on an electronic device of a user or a computer system thatis remotely located with respect to the electronic device. Theelectronic device can be a mobile electronic device.

The computer system 1501 includes a central processing unit (CPU, also“processor” and “computer processor” herein) 1505, which can be a singlecore or multi core processor, or a plurality of processors for parallelprocessing. The computer control system 1501 also includes memory ormemory location 1510 (e.g., random-access memory, read-only memory,flash memory), electronic storage unit 1515 (e.g., hard disk),communication interface 1520 (e.g., network adapter) for communicatingwith one or more other systems, and peripheral devices 1525, such ascache, other memory, data storage and/or electronic display adapters.The memory 1510, storage unit 1515, interface 1520 and peripheraldevices 1525 are in communication with the CPU 1505 through acommunication bus (solid lines), such as a motherboard. The storage unit1515 can be a data storage unit (or data repository) for storing data.The computer control system 1501 can be operatively coupled to acomputer network (“network”) 1530 with the aid of the communicationinterface 1520. The network 1530 can be the Internet, an internet and/orextranet, or an intranet and/or extranet that is in communication withthe Internet. The network 1530 in some cases is a telecommunicationand/or data network. The network 1530 can include one or more computerservers, which can enable distributed computing, such as cloudcomputing. The network 1530, in some cases with the aid of the computersystem 1501, can implement a peer-to-peer network, which may enabledevices coupled to the computer system 1501 to behave as a client or aserver.

The CPU 1505 can execute a sequence of machine-readable instructions,which can be embodied in a program or software. The instructions may bestored in a memory location, such as the memory 1510. The instructionscan be directed to the CPU 1505, which can subsequently program orotherwise configure the CPU 1505 to implement methods of the presentdisclosure. Examples of operations performed by the CPU 1505 can includefetch, decode, execute, and writeback.

The CPU 1505 can be part of a circuit, such as an integrated circuit.One or more other components of the system 1501 can be included in thecircuit. In some cases, the circuit is an application specificintegrated circuit (ASIC).

The storage unit 1515 can store files, such as drivers, libraries andsaved programs. The storage unit 1515 can store user data, e.g., userpreferences and user programs. The computer system 1501 in some casescan include one or more additional data storage units that are externalto the computer system 1501, such as located on a remote server that isin communication with the computer system 1501 through an intranet orthe Internet.

The computer system 1501 can communicate with one or more remotecomputer systems through the network 1530. For instance, the computersystem 1501 can communicate with a remote computer system of a user(e.g., a user controlling the manufacture of a slurry coated substrate).Examples of remote computer systems include personal computers (e.g.,portable PC), slate or tablet PC's (e.g., Apple® iPad, Samsung® GalaxyTab), telephones, Smart phones (e.g., Apple® iPhone, Android-enableddevice, Blackberry®), or personal digital assistants. The user canaccess the computer system 1501 via the network 1530.

Methods as described herein can be implemented by way of machine (e.g.,computer processor) executable code stored on an electronic storagelocation of the computer system 1501, such as, for example, on thememory 1510 or electronic storage unit 1515. The machine executable ormachine readable code can be provided in the form of software. Duringuse, the code can be executed by the processor 1505. In some cases, thecode can be retrieved from the storage unit 1515 and stored on thememory 1510 for ready access by the processor 1505. In some situations,the electronic storage unit 1515 can be precluded, andmachine-executable instructions are stored on memory 1510.

The code can be pre-compiled and configured for use with a machinehaving a processer adapted to execute the code, or can be compiledduring runtime. The code can be supplied in a programming language thatcan be selected to enable the code to execute in a pre-compiled oras-compiled fashion.

Aspects of the systems and methods provided herein, such as the computersystem 401, can be embodied in programming. Various aspects of thetechnology may be thought of as “products” or “articles of manufacture”typically in the form of machine (or processor) executable code and/orassociated data that is carried on or embodied in a type of machinereadable medium. Machine-executable code can be stored on an electronicstorage unit, such as memory (e.g., read-only memory, random-accessmemory, flash memory) or a hard disk. “Storage” type media can includeany or all of the tangible memory of the computers, processors or thelike, or associated modules thereof, such as various semiconductormemories, tape drives, disk drives and the like, which may providenon-transitory storage at any time for the software programming. All orportions of the software may at times be communicated through theInternet or various other telecommunication networks. Suchcommunications, for example, may enable loading of the software from onecomputer or processor into another, for example, from a managementserver or host computer into the computer platform of an applicationserver. Thus, another type of media that may bear the software elementsincludes optical, electrical and electromagnetic waves, such as usedacross physical interfaces between local devices, through wired andoptical landline networks and over various air-links. The physicalelements that carry such waves, such as wired or wireless links, opticallinks or the like, also may be considered as media bearing the software.As used herein, unless restricted to non-transitory, tangible “storage”media, terms such as computer or machine “readable medium” refer to anymedium that participates in providing instructions to a processor forexecution.

Hence, a machine readable medium, such as computer-executable code, maytake many forms, including but not limited to, a tangible storagemedium, a carrier wave medium or physical transmission medium.Non-volatile storage media include, for example, optical or magneticdisks, such as any of the storage devices in any computer(s) or thelike, such as may be used to implement the databases, etc. shown in thedrawings. Volatile storage media include dynamic memory, such as mainmemory of such a computer platform. Tangible transmission media includecoaxial cables; copper wire and fiber optics, including the wires thatcomprise a bus within a computer system. Carrier-wave transmission mediamay take the form of electric or electromagnetic signals, or acoustic orlight waves such as those generated during radio frequency (RF) andinfrared (IR) data communications. Common forms of computer-readablemedia therefore include for example: a floppy disk, a flexible disk,hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD orDVD-ROM, any other optical medium, punch cards paper tape, any otherphysical storage medium with patterns of holes, a RAM, a ROM, a PROM andEPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wavetransporting data or instructions, cables or links transporting such acarrier wave, or any other medium from which a computer may readprogramming code and/or data. Many of these forms of computer readablemedia may be involved in carrying one or more sequences of one or moreinstructions to a processor for execution.

The computer system 1501 can include or be in communication with anelectronic display 1535 that comprises a user interface (UI) 1540 forproviding, for example, parameters for producing a reduced carbonproduct. Examples of UI's include, without limitation, a graphical userinterface (GUI) and web-based user interface.

Methods and systems of the present disclosure can be implemented by wayof one or more algorithms. An algorithm can be implemented by way ofsoftware upon execution by the central processing unit 1505. Thealgorithm can, for example, regulate the flow rate of a gas streamcomprising CO₂ through a contactor unit to optimize the pH orbicarbonate concentration of an electrolyte solution. As anotherexample, the algorithm can regulate the electric field applied to amicro- or nanostructured membrane to control the selectivity of themembrane for a particular chemical species.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. It is not intendedthat the invention be limited by the specific examples provided withinthe specification. While the invention has been described with referenceto the aforementioned specification, the descriptions and illustrationsof the embodiments herein are not meant to be construed in a limitingsense. Numerous variations, changes, and substitutions will now occur tothose skilled in the art without departing from the invention.Furthermore, it shall be understood that all aspects of the inventionare not limited to the specific depictions, configurations or relativeproportions set forth herein which depend upon a variety of conditionsand variables. It should be understood that various alternatives to theembodiments of the invention described herein may be employed inpracticing the invention. It is therefore contemplated that theinvention shall also cover any such alternatives, modifications,variations or equivalents. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

What is claimed is:
 1. A system for generating a carbon productcomprising one or more carbon atoms (C1+ product), comprising: a firstcompartment; a second compartment; and a separation unit separating saidfirst compartment and said second compartment, wherein said separationunit comprises (i) an anode, (ii) a cathode, and (iii) a membranecomprising a plurality of pores, wherein said plurality of pores areconfigured to bring said first compartment in fluid communication withsaid second compartment, wherein said cathode and said anode areconfigured to reduce said carbon-containing material to said C1+ productin said first compartment while a voltage is applied between saidcathode and said anode, and wherein said plurality of pores areconfigured to direct said C1+ product from said first compartment tosaid second compartment.
 2. The system of claim 1, further comprising agas contactor in fluid communication with said first compartment,wherein said gas contactor is configured to bring said carbon-containingmaterial in contact with water to yield a solution comprising saidcarbon-containing material.
 3. The system of claim 1, wherein saidmembrane comprises one or more materials selected from the groupconsisting of carbon nanotubes, carbon nanospheres, carbon nano-onions,graphene, and porous pyrolyzed carbon.
 4. The system of claim 1, whereinsaid cathode further comprises a catalyst.
 5. The system of claim 4,wherein said catalyst comprises a metal nanoparticle.
 6. The system ofclaim 5, wherein said metal nanoparticle comprise a metal selected fromthe group consisting of copper, nickel, platinum, iridium, ruthenium,palladium, tin, silver, and gold.
 7. The system of claim 4, wherein saidcatalyst is N-doped.
 8. The system of claim 1, further comprising avoltage source configured to supply said voltage.
 9. The system of claim1, further comprising an ion exchange membrane between said cathode andsaid anode.
 10. The system of claim 1, wherein said system is configuredto have a single pass selectivity for said C1+ product of at least about70%.
 11. The system of claim 1, wherein a pore of said plurality ofpores has a pore size of less than or equal to about 5 micrometers. 12.The system of claim 1, wherein said C1+ product comprises one or moremembers selected from the group consisting of methanol, ethanol,propanol, and butanol.
 13. The system of claim 1, wherein said firstcompartment comprises said cathode and said second compartment comprisessaid anode.
 14. The system of claim 1, wherein said first compartmentcomprises said cathode and said membrane.
 15. The system of claim 1,wherein said separation further comprises an extractor.
 16. The systemof claim 15, wherein said extractor comprises said second compartmentand said membrane.
 17. A method for using a carbon-containing materialto generate a carbon product comprising one or more carbon atoms (C1+product), comprising: (a) providing an electrochemical system comprisinga first compartment; a second compartment; and a separation unitseparating said first compartment and said second compartment, whereinsaid separation unit comprises (i) an anode, (ii) a cathode, and (iii) amembrane comprising a plurality of pores, wherein said plurality ofpores bring said first compartment in fluid communication with saidsecond compartment; (b) directing an electrolyte solution comprisingsaid carbon-containing material into said first compartment to bringsaid electrolyte solution into contact with said cathode, wherein saidanode and said cathode are in electrical communication with one anotherthrough said electrolyte solution; (c) reducing said carbon-containingmaterial in said electrolyte solution while a voltage is applied betweensaid cathode and said anode to generate said C1+ product, which C1+product is directed through said plurality of pores to said secondcompartment; and (d) recovering said C1+ product from said secondcompartment of said electrochemical system.
 18. The method of claim 17,wherein said cathode further comprises a catalyst.
 19. The method ofclaim 18, wherein said catalyst is used to reduce said carbon-containingmaterial in said electrolyte.
 20. The method of claim 17, wherein saidcarbon-containing material comprises carbon monoxide (CO) and/or carbondioxide (CO₂).